Talk:Extended periodic table/Archive 3

Archive 1

Archive 2

Archive 3

Archive 4

Naming suggestions:

Superactinides could be called Unbiunides since the first 'superactinide' is called Unbiunium and we can change it once we discover it and give it a name. Unsepttrides would be the next set of superactinides since Unsepttrium is the first of such section.

Lanthanides = 15 Actinides = 15 Superactinides = 14 + 20 = 34 Another set = 34 More sets would go by this pattern: 13 + 25 = 38, 38, 42, 42, 46, 46, 50, 50, 54, 54, etc... each set being named after the first element in each set. --174.53.34.144 (talk) 13:33, 18 July 2016 (UTC)

Predicting to Group 13

I have made a periodic table predicting elements to Group 13. Link: https://plus.google.com/collection/kO_ESB --174.53.34.144 (talk) 16:00, 25 July 2016 (UTC)

I doubt that elements with large atomic numbers will follow simple extrapolation. Georgia guy (talk) 18:56, 25 July 2016 (UTC)

"or could even have completely decayed by now after having caused the radiation damage long ago"

sorry, but this is not idiomatic English (and borderline incomprehensible).137.205.183.31 (talk) 09:19, 23 August 2016 (UTC)

Really? I understand it quite simply as stating the possibility that these superheavies were around long ago and caused radiation damage as they decayed, but are gone. Nevertheless I have cut it into two sentences to make it a little more obvious: "The possible extent of primordial superheavy elements on Earth today is uncertain. Even if they are confirmed to have caused the radiation damage long ago, they might now have decayed to mere traces, or even be completely gone." Double sharp (talk) 15:19, 23 August 2016 (UTC)

Eka-superactinoids

The eka-superactinoids were removed from the template displaying the extended periodic table per consensus. But the article still has a section about the eka-superactinoids. Any discussion about whether we should remove that section?? Georgia guy (talk) 02:02, 10 January 2016 (UTC)

I've drastically cut it down, removing the detailed information about Fricke's predictions on E184, since they will likely not come to pass. It still is interesting as a historical speculation, fueled by thinking that 184 was a proton magic number (though it seems that 164 is a more likely candidate now). Double sharp (talk) 13:36, 10 January 2016 (UTC)

E? What? 108.66.234.139 (talk) 17:30, 16 October 2016 (UTC)

Double sharp is using it to stand for element. Georgia guy (talk) 17:46, 16 October 2016 (UTC)

Why not just use the atomic numbers as the name/symbol of the unnamed elements? 108.65.81.68 (talk) 15:27, 17 October 2016 (UTC)

in popular culture

So there is one story mentioning element 126. What's the significance? Double sharp (talk) 15:19, 23 August 2016 (UTC)

I saw this and deleted it even before reading the talk page:

Simon Mayo's "Itch" series concentrates on the story of a boy named Itchingham Lofte, who discovers Unbihexium (element 126). It is constantly referred to as '126' in the book, and is (fictionally) extremely radioactive. It is suggested (in fiction) to be named "Lofteinghiam".

"Itch - Element Hunter" website

If we had an article on element 126 (which redirects here), it might - with great charity - find a home there, but it makes no sense to have it in an article that is nominally about the extension of the periodic table rather than anything and I mean anything about any superheavy element. I'm not averse to seeing some of the little blurbs about certain elements here find their own articles, but that is very low on the list. :) Wnt (talk) 21:51, 27 October 2016 (UTC)

Two kinds of superactinides

Can anyone distinguish the g-block from the f-block in the eighth row rather than calling both of them "superactinides"?? Georgia guy (talk) 22:47, 13 November 2015 (UTC)

They can be distinguished by calling it 5g series or g-block series and 6f series. PlanetStar 00:20, 14 November 2015 (UTC)

There isn't expected to be much of a chemical difference between how the two behave, so why should they have separate terms? Additionally, this far into the periodic table, the blocks shouldn't mean much. Double sharp (talk) 11:43, 14 November 2015 (UTC)

How about 121 series and 139 series? 108.65.83.151 (talk) 14:46, 16 November 2016 (UTC)

This may be what you're talking about, or it may be completely different: in the chart in the "History" section, the label color for Super­actinides and Predicted are exactly the same. Maybe they're ALL predicted (I'm a designer, not a scientist) but I wouldn't know that by looking at the chart. I don't know if Wikipedia has any sort of standard colorization scheme, so I'll just leave it up to someone more knowledgeable than myself to change it, but it should be changed. BevansDesign (talk) 16:10, 12 January 2016 (UTC)

Off-topic chat

off-topic chat

Limit to all this is... The periodic table will not end at 173, in fact it will never end. This 173 limit is bogus. It was calculated in 1971, and now we know otherwise. 108.71.123.211 (talk) 01:55, 27 November 2016 (UTC) Can you prove the likeliness of element 174 as a possible creation of the (not necessarily near) future?? Georgia guy (talk) 02:04, 27 November 2016 (UTC) Congratulations for parroting Walter Greiner! Except that the 173 limit seems to have suddenly been revitalised about the time Pyykkö published his papers. You really should read and stay in touch with the latest developments. I have no problem in saying "I take back everything I said and claim the opposite" if new information comes in. So should you! Double sharp (talk) 03:27, 27 November 2016 (UTC) Try 184. 108.66.233.20 (talk) 17:25, 14 December 2016 (UTC) What about 210? 108.66.232.14 (talk) 02:47, 14 February 2017 (UTC) This article talk page is for discussing improvements to the article, not for general discussion of the article's topic. - SummerPhDv2.0

How about the large version?

https://en.wikipedia.org/wiki/Extended_periodic_table_%28large_version%29 needs an appropriate update. Droog Andrey (talk) 22:20, 4 April 2017 (UTC)

Yes, I forgot about that one. Updated. Double sharp (talk) 02:52, 5 April 2017 (UTC)

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Why 7d-elements are 155-164 instead of 157-166?

First of all, a criterion to select a group number is not the number of d-electrons but the number of valence electrons including d-shell. We have 7d¹⁰9s⁰ for element 164 as well as 4d¹⁰5s⁰ for palladium; elements from 157 to 162 has from 3 to 8 valence electrons (over closed 5g¹⁸6f¹⁴8s²8p² shell), as well as elements from lutetium to osmium (over closed 4f¹⁴ shell).

Secondly, elements 165 and 166 seem to be too far from being alkali and alkali-earth metals. The soft 7d subshell under valence 9s electrons makes these elements similar to silver and cadmium, and maybe both of them (or at least element 165) could still use their 7d electrons for chemical bonding.

Thirdly, elements 155 and 156 have their 6f subshell still opened for chemical bonding, making them similar to mendelevium and nobelium, so they shouldn't count as 7d-elements.

To make all of that clear, let's remember that all of these elements are metals, so their chemical nature is better described by electronic structure of their cations instead of neutral atoms. When atom is positively ionized, a few things happen:

• subshells with higher l number are generally drowned deeper because of less screening, e.g. for Ca²⁺ 3d lies below 4s, while for neutral Ca 3d lies above 4p;
• atomic levels become less dense, making core, valence and free subshells easier to distinguish;
• those exceptions from Madelung's rule which has no chemical significance (e.g. for Cr, Cu, Nb-Pd, Pt, Lr) are vanished.

Thus, for metals the periodic trends are far better described by configurations of dications instead of neutral atoms (after element 122 the given configurations may appear a bit higher than the ground state, but at least they are close to the ground state).

a proposed look of periodic table

That's why I propose a somewhat simpler and less detailed template for extended periodic table, looking like this:

Note that it has little sense trying to separate 5g and 6f blocks since both of them has quite uncertain starting bounds. However, the 18-electron capacity of 5g yields some correlations along two subsets 121-138 and 139-156 since both of them have 18-element length. Elements of the subset 121-138 have up to 6 valence electrons (like 6f²8s²8p² with 8s² gradually drowning into the core) and are very similar just like lanthanides overall, while the subset 139-156 reminds actinides: first elements has an increasing number of valence electrons (6f^k7d²8p²), but then 6f subshell is buried down along with 8p, leaving only 7d² electrons easy to remove (as well as 7s² electrons in nobelium).

After all, that's not an original research: the corresponding model was introduced in 2006 by Nefedov et.al.; here's the paper: http://www.primefan.ru/stuff/chem/nefedov.pdf

So, again, I propose that simple model with elements 157-172 belonging to groups 3-18 as the best guess to their chemical nature, and elements 121-156 separated as two 18-element subsets according to their complicated electronic structure and overall likeness to lanthanides and actinides, respectively. Droog Andrey (talk) 12:40, 7 March 2016 (UTC)

Revived from the archive to make the next section clear (it refers to this one). Droog Andrey (talk) 09:17, 27 July 2017 (UTC)

Location of the 6f series

According to predictions, the whole set of the elements 121-156 has their 6f subshell available for chemical bonding, and it is quite difficult to exactly locate the 6f series. But we may look at the earlier periods: 5d electrons appear in La and Ce, way before the 5d series; 6d subshell is populated in many actinides; 7p electron is active in lawrencium before p-block. So we see that p, d and f-blocks correspond to the valence subshells with highest angular momentum, with possible exceptions for Zn and Cd. Indeed: Ac and Th use their 5f, 6d, 7s and probably 7p subshells, which make them members of f-block, while Lr use only 6d, 7s and 7p and is a member of d-block.
Looking at the configurations of elements 121-172 predicted by various authors, we may notice which subshells are probably valence either as highest occupied (HO) or as lowest unoccupied (LU):

• elements 121-142 use 5g, 6f, 7d, 8s, 8p_1/2 subshells as HO or LU, so they might belong to g-block;
• elements 143-156 use 6f, 7d, 8p_1/2 subshells as HO and maybe 9s as LU, so they might belong to f-block;
• elements 157-166 use 7d and 9s subshells as HO and 9p_1/2+8p_3/2 as LU, so they might belong to d-block;
• elements 167-172 use 9s and 9p_1/2+8p_3/2 as HO, so they might belong to p-block.

The most arguable thing is the precision of these bounds. 7d-series, from 157 to 166, is discussed in the previous section; let's now concentrate on the bounds for 6f series.

Pekka Pyykkö's computations show that element 142 is the last one where 5g and 8s subshells are still open for chemical bonding. Although the neutral atoms of elements 143 and 144 has probably still unfinished 5g-subshell, it become 5g¹⁸ when atom is positively ionized (the reason was mentioned in the previous section: subshells with higher angular momentum are drowned deeper because of less screening). On the other hand, positive charge is the only way to reach 5g orbitals for (at least indirect) chemical bonding because of their small size. Therefore, element 142 is a good candidate for the end of g-block.
So, 6f series is probably started at element 143 since its 6f subshell has the highest angular momentum among valence subshells 6f, 7d and 8p_1/2. As for the right end of the 6f series, most of the authors agree that 6f become filled near element 156. Pekka Pyykkö shows that triple cation of element 155 has 6f¹⁴ and still may be chemically ionized further (the calculated ionization potential for Upp³⁺ is higher than for Tb³⁺, but lower than for Dy³⁺). Other authors predict a bit higher energy of 6f subshell in the vicinity of Z=156, but all of them agree that for Z=158 the 6f subshell is buried deep down together with 8p_1/2.
Taking all of this into account, it might be possible to formally assign:

• elements 121-142 to g-block (although 5g is empty for a few first elements, it is used as lowest unoccupied subshell, just like 5f for Ac and Th);
• elements 143-156 to f-block (although we need more accurate predictions to see a tight deadline where 5g subshell becomes inactive);
• elements 157-166 to d-block (although 7d subshell is probably inactive in element 166, that's the very case for zinc (3d) and cadmium (4d), so the analogy resists);
• elements 167-172 to p-block (although there's no pure 8p subshell, a hybrid 9p_1/2+8p_3/2 will go well for 8th period).

But then we should certainly make a warning that this is only a rough pattern, while the real chemistry of these elements is far deeper, and now we have no calculations precise enough to make more detailed arrangement of elements in 8th period. Droog Andrey (talk) 15:17, 8 March 2016 (UTC)

That's how it will look like.

I support this. You make a lot of sense and argue based on many reliable sources. (I'll need to rewrite the part about 165 and 166 to make it clear that they are probably going to be closer to IB and IIB than to IA and IIA, though that does not, of course, bar them from having some characteristics of the latter.) Like you, I don't think we can say any more till more theoretical studies appear, or we synthesise all the period 8 elements till 172 (and I am very doubtful that either of us will live to see that). Double sharp (talk) 15:33, 8 March 2016 (UTC)

(I really like this development. Looks great). -DePiep (talk) 20:51, 11 March 2016 (UTC)

I can't see the far left of that image; there's no scroll option. This image is just like simple extrapolation except that the g-block has 22 elements instead of 18. Any corrections to what I'm saying?? Do 4 of the 22 elements in the 121-142 interval belong to a special block?? Georgia guy (talk) 21:03, 11 March 2016 (UTC)

(Just click the image, and you arrive at the image view for a complete viewing). It's not a simple extrapolation. It is a careful and helpful representation of the sources. It really helps the average Reader (trust me). -DePiep (talk) 21:25, 11 March 2016 (UTC)

The main comment I have is that I support that, in an appropriate position, this article needs an image of the periodic table made by simply extrapolating the periodic table. Yes, the article has a message saying "Although simple extrapolation..." for clarification on what it would be. Georgia guy (talk) 21:32, 11 March 2016 (UTC)

I don't get what you mean, because I only can talk about the graphics (including the horizontal scrolling option; it'll be allright in any article for sure). For the textuals like Although simple extrapolation... (sure that is a bad article approach!), I leave that to other editors here on this talkpage. -DePiep (talk) 22:07, 11 March 2016 (UTC)

(I'm very, very interested where this conversation between Droog Andrey and Double sharp leads to. Will be a great article improvement, also into Readers' like me understanding (that is: clarifying). Now back to the main topic.) -DePiep (talk) 23:17, 11 March 2016 (UTC)

A periodic table by "simple extrapolation" would look exactly the same, but would end the g-block at 138 instead of 142. (So, for example, 168 would be under 118 instead of 172.) Double sharp (talk) 09:36, 12 March 2016 (UTC)

Let's make a difference between "simple extrapolation" and "extrapolation of Madelung's rule". The variant with element 168 in the VIIIA group is just a meaningless venture to pull the Madelung's rule beyond 7th period where it doesn't work because of progressive relativistic effects. The variant I proposed is indeed a simple extrapolation, but it is overall supported by rough quantum-chemical calculations. To ensure any more detailed arrangement of the elements (say, to prove some explicit bounds on some special series and so on), we should wait for some deep calculations of atomic and molecular species with at least MRCI level of theory with high-order relativistic hamiltonian. Droog Andrey (talk) 23:45, 13 March 2016 (UTC)

You're right, of course, but your extrapolation is not really conceptually simple. It looks simple, but you can only get to it via relativity, so perhaps it could be stated to be based on a more detailed, relativistic look at the situation. Meanwhile, we could clarify the wrongness of the Aufbau extrapolation by calling it a naïve extrapolation. Double sharp (talk) 15:20, 14 March 2016 (UTC)

Sounds good to me. Droog Andrey (talk) 20:12, 14 March 2016 (UTC)

I reread Fricke's paper, and even he (what with his placement of 164 under Hg and Cn) says it is most analogous to group VIII (= 10). In fact, he writes in Table 6 that 157 should be most similar to group IIIB, 158 to group IVB, and so on. As for 165 and 166, Fricke puts them in IA and IIA, citing predicted ionisation energies which fit the trend in these groups better than those in IB and IIB. But he also admits that 7d will be active chemically, which is unlike the behaviour of IA and IIA, because it is easier to penetrate a filled d¹⁰ shell than a filled p⁶ shell. Since chemical properties form the basis of this whole extrapolation, I think we really should change this to the format proposed above.

Double sharp (talk) 14:50, 2 August 2016 (UTC)

P.S. Regarding 167–171; I cannot imagine an element with such density being a nonmetal or metalloid, and I only mark 171 as such for its chemistry. Double sharp (talk) 15:02, 2 August 2016 (UTC)

That looks very good. Droog Andrey (talk) 21:27, 13 September 2016 (UTC)

All right, I've made the changes!

I should note that we are considering moving group 12 to the post-transition metals. Element 166 would be similarly affected since it is much less sure if 7d¹⁰ will be active there than at element 165. Double sharp (talk) 01:44, 13 October 2016 (UTC)

This categorization violates WP:OR. --Abelium (talk) 17:03, 14 October 2016 (UTC)

• elements 157-164 to d-block
• elements 165-176 to s-block
• elements 167-172 to p-block (although there's no pure 8p subshell, a hybrid 9p_1/2+8p_3/2 will go well for 8th period).

I propose this categorization. --Abelium (talk) 17:03, 14 October 2016 (UTC)

No it is not OR. Paper. Double sharp (talk) 02:23, 15 October 2016 (UTC)

Furthermore, even Fricke's original paper assigns element 157 to the "chemically most analogous group" IIIB, all the way to 164 at VIII. Even though he places 165 and 166 as close to IA and IIA, he also notes that they would have substantial similarities to IB and IIB. OR? I think not, when even the papers being cited equivocate on exactly which groups these elements are in, and it was pretty easy to find a paper giving the current classification. And I can see you haven't actually read the whole discussion, or even looked at the papers involved, or else you would have noticed this. Double sharp (talk) 02:25, 15 October 2016 (UTC)

This paper did not explicitly mention about E165-172. Furthermore, E164 and E163 are very dense elements, but E165 and E166 are not. Chemical consensus is E165-E172 are Period 9 elements. --Abelium (talk) 08:58, 15 October 2016 (UTC)

Your last sentence is demonstrably false: Pyykkö's paper certainly places E169–E172 in period 8. Leaving aside that the density estimates are first approximations only, I'm not particularly surprised that the density falls down after the 7d-shell finishes filling. Remember that 9s has only just fallen down to be permanently energetically favourable to occupy (this must be a close thing, because the earliest Fricke calculations don't predict 9s involvement in E156–164), and there is a great deal more stuff in the core than usual (instead of adding 5f shielding in period 7 at Rg, we now have shielding by 5g, 6f, 8s, and 8p_1/2). That the 9s electron would then be really far from the nucleus is therefore not unexpected in E165 and E166 – but even according to Fricke et al., 7d has not sunk into the core yet at E165.

Furthermore, we seem to agree that E167–E172 are members of groups IIIA to 0. If E164 is in VIII, and E167 is in IIIA, there is an unsightly gap that could be easily filled if E165 and E166 were members of groups IB and IIB. And, lo and behold, look what Fricke et al. write: "From the normal continuation of the periodic table one would expect that after the completion of a d shell (at element 164) two elements in the IB and IIB chemical groups should appear. In a very formal way this is true, because with the filling of the 9s electrons in elements 165 and 166 there are outer s electrons chemically available." They then admit that this has some problems because these are not the same 8s electrons that began the period way back at E119, and that they also show some characteristics of IA and IIA because 9s is further from the nucleus than would be expected (see what I wrote in the previous paragraph). But, and this is the key point, Fricke et al. note that they would still be transition metals. Thus they write "This classification [of E165 and E166 as members of groups IA and IIA] is, of course, not entirely, satisfactory in every respect because from a more chemical point of view these elements will also show characteristics of the IB and IIB groups because of the underlying 7d shell. Therefore, higher oxidation states than +1 and +2 might readily occur." That settles it IMHO, as Greenwood and Earnshaw wrote: "the first ionization energies of the [group IB elements] are much higher, and their ionic radii smaller than those of the corresponding alkali metals. They consequently have higher mps, are harder, denser, less reactive, less soluble in liquid ammonia, and their compounds more covalent...a filled d shell is more easily disrupted than a filled p shell...they are able to adopt oxidation states higher than +1. In short, Cu, Ag and Au are transition metals whereas the alkali metals are not." Indeed, comparing E165 with E119, the previous alkali metal, we see a higher (though not as high as usual because 9s is a little further than usual) ionisation energy, a smaller atomic radius, almost double the density, and a willingness to breach the inner 7d subshell. This is clearly transition-metal behaviour, chemically. At the very most you could have E165 like silver, preferably forming the +1 oxidation state but still allowing the shell to be breached (as well, look at how Ag falls down in density from the previous elements as 4d sinks almost into the core, and how the group 12 elements fall down even more). Double sharp (talk) 11:48, 15 October 2016 (UTC)

Lastly, despite Fricke et al. daring to call E119 and E120 "alkali" and "alkali earth", they do not do so in the table for E165 and E166, contenting themselves with "IA" and "IIA" (and implying "IB" and "IIB" in the text). Double sharp (talk) 12:44, 15 October 2016 (UTC)

Just preventing from falling into archive. Droog Andrey (talk) 23:27, 14 October 2017 (UTC)

Walter Loveland quote

"Does the Periodic Table have limits? YES!! At some point (Z~122) all the electron energy levels of adjacent elements are similar so that there are no differences in their chemical behaviour." (source).

This is the explanation of Droog Andrey's initial colouring of all the superactinides as one group, without breaking it into a g- and an f-block: it gets very difficult to break things into separate "blocks" past Z = 122, because 5g, 6f, and 8p_1/2 are all mixing and are very close to each other; 7d is somewhat further, so we still get a reasonable transition series ending at Z = 166. (It is rather convenient that a "second island of stability" is expected to surface around Z = 164, right as we get out of the woods of the superactinides, so that the elements which we will be able to chemically investigate first will be the ones that make increasingly more sense in terms of what we already know in the first seven periods, until we reach eka-oganesson at Z = 172 in the next century.) Even the current colouring of "blocks" is rather formal and doesn't quite correspond to what we normally think of as the blocks: for instance, the g-block is shown with twenty-two columns, although there is only room for eighteen electrons in the 5g shell. It's almost as if the h-block, sad that it was never going to get filled up before weird things started happening at Z = 173, decided to infiltrate the g-block and make it have its characteristic twenty-two instead of eighteen columns. ^_^ More seriously, the lack of distinct chemical behaviour between elements filling the g-, f-, and p-orbitals in this region shows what Loveland is referring to here as the limits of periodicity.

It is still worth noting that all the extrapolations I am aware of past Z = 122 are incomplete in one way or another, so that these shores are largely still unexplored. But it is still useful to have a map to guide us as far as it can, even if between Z = 122 and Z = 157 it says "here be dragons"! ^_^ Double sharp (talk) 16:03, 29 March 2017 (UTC)

Aufbau variant

What's the point to place it into the article? https://en.wikipedia.org/wiki/Extended_periodic_table#Extended_periodic_table Droog Andrey (talk) 11:23, 4 February 2018 (UTC)

I could see reason for placing it in a "History" section, as it was the original one Seaborg suggested. I do agree though that this is not the best spot for it. Double sharp (talk) 11:38, 4 February 2018 (UTC)

Interesting remark on element 173 (which may well be considered a good alkali metal)

From primefan.ru: "Однако для Z > 155 обнаруживается весьма интересное стечение обстоятельств: сближаются по энергии 7d- и 9s-подслои, а затем 8p_3/2 и 9p_1/2, после которых образуется большой энергетический зазор. ... По всей вероятности, туннельные эффекты не позволят существовать атомам элемента №173 продолжительное по химическим масштабам время, даже если будут получены его относительно стабильные по отношению к ядерному распаду изотопы (что само по себе крайне маловероятно). Расчеты при этом указывают на то, что единственный валентный электрон этого элемента будет находиться на 6g-подслое и иметь столь высокую энергию, что цезий по сравнению со 173-м можно будет считать металлом невысокой активности." (Attempt at translation forthcoming tomorrow; I'm out of time today.) Double sharp (talk) 15:41, 21 February 2018 (UTC)

Please translate that into English. Georgia guy (talk) 15:44, 21 February 2018 (UTC)

This means: "However, for Z>155 there is evidence for quite an interesting combination of circumstances: 7d and 9s subshells are close in energy, and so are 8p_3/2 and 9p_1/2, after which there is a large energetic gap. ... In all probability, tunnel effects do not allow element 173 to exist for a time enough for chemical investigation, even if its relatively stable towards nuclear decay isotopes will be synthesized (which is by itself highly improbable). Meanwhile, calculations indicate that the only valence electron of this element belongs to the 6g subshell and its energy will be so large that caesium when compared to 173 may be considered a metal of low activity." Burzuchius (talk) 20:44, 21 February 2018 (UTC)

That's my old popular-science article for high schoolers. Since then I realized that Z > 173 is really not a problem (see below).Droog Andrey (talk) 21:06, 24 February 2018 (UTC)

Elements 173 and 174

Just recently, Double sharp made an edit saying that element 173 is expected to be an alkali metal. If this is true and creating element 173 is possible, then creating element 174 should be just as difficult, assuming it's the corresponding alkaline earth metal. Any flaw?? (In determining what to say on this section of the talk page, please include your opinions on whether each of element 173 and 174 should be included on the table of elements in this article that Double sharp recently added element 173 to as an alkali metal.) Georgia guy (talk) 00:19, 22 February 2018 (UTC)

It's not entirely clear what exactly happens once you pass Z = 173 and the 1s electrons dive into the negative continuum, but whatever does happen may not allow such atoms to stick around long enough to be considered elements. In other words, though 173 may or may not give problems, from 174 onwards there are likely to be problems, and things are expected to be different enough that we cannot promise anything. Besides, I don't see predictions about element 174 in any reliable source yet, so 173 should be in and 174 should be out. This sort of stability is rather divorced from what happens to be in the outer shells.

As for the chemistry: remember that the 6g, 7f, and 8d shells are expected to be of rather similar energy and all really quite a lot higher up than the shells filled up in the [E172] core; E184 should have some of each. Thus I am inclined to think that early expectations of very high oxidation states for such elements would turn out to be roughly on the mark. It seems likely that a comparison of E184, like Fricke gives, to U and Np is plausible: it would likely be an electropositive metal (perhaps more so than the actinides) showing variable oxidation states, as expected since the 6g orbitals have radial nodes that are absent in the 5g orbitals. The 10s and 10p_1/2 orbitals may also join in the fun later, though I'm sceptical about 6h (Fricke gives 5h, but this is clearly a mistake) due to its high angular momentum. Double sharp (talk) 01:19, 22 February 2018 (UTC)

BTW it should also be noted that the difficulty of creating eka-francium and eka-radium should vary significantly with the target–projectile reaction that is being used (the more asymmetric the better). As for dvi-francium and dvi-radium (assuming that it's not a problem for the 1s shell to dive into the negative continuum), we should also remember that target–projectile reactions are highly suspect as a way to reach elements on the second island. If you accelerate uranium ions at a uranium target you can hardly expect to make any atoms of element 184. At the most you might have a transfer reaction and make an early period 8 element, but hardly a late period 8 element. When we gain the technology to probe the region around the magic number 164, I suspect that different methods will be in use (although I am not sure either of us will live to see it), and I am quite sure that they will show just as much if not more variability. Double sharp (talk) 05:10, 22 February 2018 (UTC)

AFAIK, there's no problem with negative continuum for Z > 173 except for some issues about positron scattering. There's a good article on this (sorry, in Russian). Droog Andrey (talk) 20:56, 24 February 2018 (UTC)

@Droog Andrey: Very interesting (and I'm sorry that I can't understand it). Does the article at least give a summary on what happens once the 1s subshell dives into the negative continuum? Is it anything like what Joachim Reinhardt and Walter Greiner say in this article? I'll give a few quotes:

The electric field strength at the surface of a nucleus exceeds E_cr [= ⁠πm²c³/eħ⁠] by about three orders of magnitude. Nevertheless in ordinary atoms pair creation does not occur because the created electron quantum mechanically would not fit into the narrow well of the Coulomb potential. This changes when atomic structure is extrapolated from the known region of chemical elements by about a factor of two. As discussed above, supercriticality sets in at Z_cr ≃ 172 when the 1s_1/2 state "dives into the lower continuum" and is transformed into a resonance.

In the language of Dirac's hole picture, if an empty bound state enters the lower continuum it will get filled by a sea electron which can tunnel through the classically forbidden gap of the Dirac equation, leaving behind a hole, i.e., a positively charged positron, which escapes to infinity. This is just an instance of the Schwinger mechanism for pair creation. The process also has been termed "spontaneous pair creation" or "decay of the vacuum" of QED. The difference to Schwinger pair creation in a constant electric field is that in supercritical atoms the strong field is confined to a small region in space which can harbour only a small number of created electrons. I.e., pair creation is stopped by "Pauli blocking" when the available electron states are occupied. In a weakly supercritical atom (172 < Z < 185) just two positrons (spin degeneracy) can be produced in this way.

In a world with a fine structure constant α somewhat larger than our physically realized value supercritical atoms would be an everyday phenomenon. It would be impossible to fully ionize heavy atoms since their inner shells would be filled by "electron capture from the vacuum" (bound-free pair creation). The supercritical atoms would exhibit narrow resonances in the scattering of positrons.

I notice that they cite as their reference [4] a paper also by Zel'dovich and Popov, though dated 1972 rather than the 1971 of your article. This would seem to mean that there is no problem other than the limitations of nuclear stability, even as 1s_1/2 dives into the negative continuum around Z = 170 and 2p_1/2 and 2s_1/2 around 185 and 245 respectively. (It looks like I'll have to rewrite this piece again to take this into account.) Double sharp (talk) 14:06, 25 February 2018 (UTC)

P.S. Their reference [3] has doi 10.1007/BF01398198, and the following chapter in Nuclear Physics: Present and Future also contains some information on experimental probing of this supercritical region. It really does look like I will have to rewrite some of the later sections again: what a shame it is that I can't find any chemical predictions on the ninth period past its opening at E173 and the glimpse of the "eka-superactinides" at E184! Double sharp (talk) 14:53, 25 February 2018 (UTC)

That's the same article. It was probably translated to English in 1972. There's a short quote from it:

4.4. До сих пор мы рассматривали голые ядра. Если же уровень 1S занят электронами, то при переходе через Ζ = Zc никаких видимых эффектов не возникает. Электронное облако, несущее заряд —2е, образуется при Ζ < Zc двумя электронами на нижнем (дискретном) уровне, а при Z > Zc — возмущением функций континуума вблизи энергии ε = ε0 < —1. Если проинтегрировать плотность зарядов по всему непрерывному спектру, то при Ζ > Zc получится (после перенормировки) как раз лишний заряд —2е. Хотя формально K-оболочка при Ζ > Zc исчезла (из одночастичных решений уравнения Дирака), но ее роль берет на себя сплошной спектр. Поэтому, например, электроны внешних оболочек атома каких-либо изменений в точке Ζ = Zc в этом случае не замечают.

A quick translation:

4.4. Until now, we have considered bare cores. But if 1S level is occupied by electrons, no visible effects appear when passing through Ζ = Zc. An electron cloud carrying a charge —2e is formed either by two electrons at the lower (discrete) level for Ζ < Zc or by perturbation of the continuum functions near the energy ε = ε0 < —1 for Z > Zc. If we integrate the charge density over the entire continuous spectrum, then for Ζ > Zc we get (after renormalization) exactly an extra —2е charge. Although formally the K-shell for Ζ > Zc is disappeared (from single-particle solutions of the Dirac equation), its role is assumed by the continuous spectrum. Therefore, for example, the electrons of the outer atomic shells do not notice any changes at the point Ζ = Zc in this case.

Droog Andrey (talk) 20:37, 25 February 2018 (UTC)

@Droog Andrey: Fascinating, thank you! I see the standard term for atoms with Z > Z_cr is "supercritical atom" (e.g. here). I'll soon do the necessary rewrites. Double sharp (talk) 04:43, 26 February 2018 (UTC)

I have added a brief mention of supercritical atoms and mention that Z ≈ 173 looks like it is not going to be a limit either. I suppose that the real end is going to be dictated by nuclear properties; has anyone predicted where that would be? Double sharp (talk) 15:31, 11 March 2018 (UTC)

Why would period 8 end at Usb instead of Uho?

The 5g won't have 22 electrons given that square numbers are 1, 4, 9, 16, 25,..., not 1, 4, 9, 16, 27,... So Uho is noble gas, Uhe is alkali metal, Usn is alkaline earth and Usu to Ust are the last subcritical elements, being superactinides. 80.98.179.160 (talk) 11:41, 20 March 2018 (UTC)

It's all covered in the article. 5g still has 18 electrons, but it's not the only one being filled. Speaking of blocks here is a little silly, but after 8s fills at elements 119 and 120 we have lots of shells with similar energy levels that overlap. The ground-state electron configurations of the neutral atoms (given in the article) are a complete mess with lots of overlap, but if you consider doubly charged cations you can simplify what happens. A reasonable way to account things would be to say that two electrons of 8p (elements 121 and 122) and two electrons of 6f (elements 123 and 124) fill up before 5g proper (elements 125 to 142), so the run of eighteen is delayed (so these elements should be predominantly hexavalent or more, losing the outer 6f²8s²8p² electrons, although promotion of one or two inner 5g electrons like the lanthanides do with their 4f electrons may be possible). Then the rest of 6f fills (elements 143 to 154) creating a series similar to the actinides (where at first the 6f electrons are all mostly chemically active, but at the end everything starts to fall into the core), before 7d (elements 155 to 164) and 9s (elements 165 and 166). (Because of the very long inner transition series the effective nuclear charge has risen so much that 8s is completely drowned into the core; the relativistic stabilisation of the s-shells that penetrate the nucleus also means that 7d is closer in energy to 9s than 8s.) Then we get two electrons of 9p (elements 167 and 168 – the p-subshells are split) and then finally the rest of 8p (elements 169 to 172). (It should be emphasised that though this narrative of when each electron shell is filled is based on the electron configurations given by Fricke, and is partly based on the comments he gives, there are likely to be no real boundaries here between blocks in the sense that the chemistry of the superactinides is likely to be a narrative of continuous change instead and the blocks are only formal.) So in addition to the Madelung 8s-5g-6f-7d-8p sequence we get four extra electrons from the 9s and part of the 9p subshells along the way, extending the row from 168 to 172. Double sharp (talk) 13:53, 20 March 2018 (UTC)

P.S. This has some similarities to the "intruder levels" of the nuclear shell model, which should have been part of the next shell but are lowered by spin–orbit coupling effects. In fact it is also why the next proton magic numbers past 82 are predicted to be 114 and 164, rather than 126 and 184 as would be expected (continuing the pattern and following known and expected neutron magic numbers). Double sharp (talk) 06:30, 26 March 2018 (UTC)

Access date

@Headbomb: Just wondering, how do you justify the |access_date= in your recent edits? YBG (talk) 04:53, 2 August 2018 (UTC)

P.S., by rights, WP:BRD says you should not have restored your bold edit that I reverted without first discussing it here. YBG (talk) 04:53, 2 August 2018 (UTC)

I have no idea what you're talking about by "justify the |access_date=". There were no urls, so I removed the access-date, this is standard stuff. You seem to be under the impression that I somehow added accessdates. Headbomb {t · c · p · b} 05:17, 2 August 2018 (UTC)

Let me double-check. YBG (talk) 07:38, 2 August 2018 (UTC)

I was absolutely wrong, you removed the |access_date= along with the url. I have no idea how my carelessness occurred, but carelessness it ws, and you have my heart-felt apologies. Thank you for WP:AGF! Happy editing! YBG (talk) 07:44, 2 August 2018 (UTC)

Expert tag, December 2011

Over the past few weeks, I was brushing up and expanding this article, hoping to prepare it for a GAN. There is, however, a tag dated December 2011 requesting expert attention. This tag has lingered for seven years despite substantial growth and does not clearly refer to a specific problem in the article. I am unsure how to address it (or if it should still be here), and I am doubtful a GAN will succeed if whatever underlying issues remain unnoticed. ComplexRational (talk) 00:34, 10 December 2018 (UTC)

Was added here, section had one ref. Looks like section has been rebuild since. I think we can rejudge section quality today (that is, delete the tag when we think current version is OK). -DePiep (talk) 00:44, 10 December 2018 (UTC)

There are definitely more sources that clearly outline Pyykkö's predictions (that I don't think existed then or were perhaps not known within the WP community - the main one is dated 2011) and the rest of the article gives some implications as to why, and I am not left confused or longing for more information after reading that section. I still would like everyone's opinion before considering removal of the tag. ComplexRational (talk) 01:39, 10 December 2018 (UTC)

At the time the expert tag was added, there was another one which was removed by DePiep in this edit, saying that three sources was enough to remove the tag. This section now has two sources, one used twice. Do we think that is enough? YBG (talk) 02:33, 10 December 2018 (UTC)

To me, the two sources look adequate, as the main one (PT172) is quite complete and everything else I've found includes a reference to that original one, without providing further information on calculation or generic predictions not already explained. ComplexRational (talk) 23:53, 10 December 2018 (UTC)

Counting sources of course is not exactly enough to remove the {{Expert needed}} tag. IMO, since the tag was added the section was rewritten (e.g., by editor Double sharp, do we need more 'expert'?). Also, the {{Expert needed}} documentation is quite clear in its opening description: 1. don't add it as a blanket, but be specific (talkpage or add the reason); 2. may be removed when unexplained; 3. do not expect a response. In this case I conclude: we have taken a look, we can remove the tag for all these reasons, unless someone wants to explicitly keep it in here. -DePiep (talk) 08:42, 11 December 2018 (UTC)

Very sound reasoning. After a couple more days with no objections, we can safely remove it. YBG (talk) 17:32, 11 December 2018 (UTC)

Agreed with YBG, especially on point 1 per documentation. ComplexRational (talk) 21:37, 11 December 2018 (UTC)

Y done [1] -DePiep (talk) 22:16, 11 December 2018 (UTC)

Pyykkö's justification for putting E165 and E166 in the s-block rather than the d-block

To quote his paper: "As seen from Table 3, the dication E166² strongly prefers a 7d¹⁰9s⁰ configuration to the alternatives 7d⁹9s¹ or 7d⁸9s². We recall here that Rg (E111) prefers a 6d⁹8s² [sic] ground state⁵². Due to this orbital order 7d < 9s, we therefore let E165 and E166 stay in Groups 1 and 2, as done by Fricke et al." So he is comparing the situation 7d < 9s in the 7d series with the situation 6d > 7s in the 6d series. OTOH, it seems to me at least that this makes the 7d series more analogous with the 3d, 4d, and 5d series, which have 3d < 4s, 4d < 5s, and 5d < 6s respectively as we learn in high-school chemistry. ^_^ Alas, Pyykkö does not tabulate ionisation energies of E165 and E166, which would be an interesting comparison to the Cu and Zn groups. Double sharp (talk) 16:06, 2 February 2019 (UTC)

This statement by Pyykkö changes the principal setup of the periodic table: 1. increasing atomic numbers, 2. rows to point to periodicity (together I call these Mendeleevian). Of course this is all right, it's only that we should not present this as just one more editorial variant periodic table (not). I am not disputing the scientific base, I want to note that this change of structure requires that we at least qualify the naming: "periodic table (by Pyykkö)". Similar, because of different structural setup: Timothy Stowe (or [ADOMAH; truly 4D of course per QM), and especially when extended: by Aufbau (DOA?), by Fricke, by Nefedov. btw I think "periodic table (by Janet, aka left step)" is Mendeleevian. It is no small step when the periodic law leaves the original discovery of the principle, so a deviation should be added to the name. Regarding group 3: if new knowledge requires that the PT breaks Mendeleevian rules (so far, we at enwiki do not say so), then we need "periodic table (by electron configuration considerations)". -DePiep (talk) 19:08, 3 February 2019 (UTC)

Proposed merge with Extended periodic table (detailed cells)

Per AfD. Useless WP:NOTSTATS duplicate. wumbolo ^^^ 14:35, 2 February 2019 (UTC)

Wumbolo could you link to that AfD discussion? -DePiep (talk) 14:38, 2 February 2019 (UTC)

Here: Wikipedia:Articles for deletion/Extended periodic table (large version). The closer recommended a merge proposal. wumbolo ^^^ 14:46, 2 February 2019 (UTC)

Wumbolo This is the full closing conclusion from 2012:

The result was keep. If someone wishes to merge it with any other article, please take it up on this article's talk page.

So there is no merge "recommended"ation, as you wrote here. The AfD closing brings no argument for or against any merge(-proposal). -DePiep (talk) 14:20, 3 February 2019 (UTC)

Seems like a good idea, but you should probably mention it on Talk:Extended periodic table (detailed cells) — Preceding unsigned comment added by Notrium (talk • contribs) 14:53, 2 February 2019 (UTC)

• Support No brainer, the table should certainly be on that main article rather than a separate page. Reywas92^Talk 19:48, 21 April 2019 (UTC)

A few additions

I have added some material, with the help of Google Translate to understand the Russian, from Droog Andrey's "old popular-science article for high schoolers" (as he put it in the archive). As he is a subject-matter expert and has been published in the relevant field of computational chemistry (for example here), I believe this may be considered reliable as such cases are an explicit exemption on our self-published sources policy. It is interesting to see that the part of period 8 covered by the islands of stability indeed looks pretty non-relativistic: 119 and 120 look analogous to Rb and Sr, with 157–172 being good analogues of Y through Xe indeed, and 173 finally grants us our wish for the greatest alkali metal explosion! Meanwhile 121–138 and 139–156 respectively mimic the lanthanides and actinides. Double sharp (talk) 15:08, 23 July 2019 (UTC)

Some quotes from the Fricke papers on why we depart from their suggested periodic table layout

So why do we put E164 in group VIII? Well, they also wanted to!

[In the following I am mostly using the old CAS-style A/B notation, in which the B is used for the d-block groups, to be consistent with the source. The source does use "VIII" and "0" instead of "VIIIB" and "VIIIA", though. If you have a problem with it, the concordance is as follows:

IA	IIA	IIIB	IVB	VB	VIB	VIIB	VIII			IB	IIB	IIIA	IVA	VA	VIA	VIIA	0
1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18

In particular VIII refers to three columns.]

From the paper in Actinides Reviews, 1 (1971) 433–485 (my commentary in brackets):

"Even for the neutral atom, a similarity can be seen between Pd where ten d electrons and no s electrons form the outer shell and element Z = 164." (We might add that the state of affairs in the 7d row, where at most only one electron is promoted to the 9s orbital, and often none are, is like an extended version of the trend that we can see happening in the 4d row, if relativistic effects had not intervened for the 5d and 6d rows.) "Pennemann et al. ... agree with Fricke et al. that the metallic form might be quite stable but they compare it more with Hg whereas Fricke et al predict E164 to be a noble metal which should be in the same chemical group as Pd and Pt." (This placement naturally fixes the position of the preceding d-elements.)

"Here the trend becomes very obvious that the radii and ionization energies of alkaline and alkaline earth elements increase with Z whereas in the first part of the Periodic System they decrease. From this side E165 and E166 will be members of the groups Ia and IIa. From a more chemical point of view, they will be likely more members of the Ib and IIb groups because of the 7d shell which is more comparable to the elements Au and Hg (but also to the elements E119 and E120) as can be seen from Fig. 14. Therefore, higher oxidation states than 1 and 2 might readily occur." (It also seems to me that the placement of E165 and E166 in groups IA and IIA is a symptom of normalising relativistic effects and forgetting how things work in the normal part of the periodic system that we usually deal with, as I noted two sections ago. Not only is the 7d < 9s situation comparable to the normal 3d < 4s, 4d < 5s, and 5d < 6s situations rather than the odd 6d > 7s situation, but also one of the key points of chemistry is that there is a large energy gap between a closing p-shell and the s-shell of the next principal quantum number, so you cannot take electrons out of an earlier shell. We accept it, perhaps, for E119 and E120 because we then have no choice, but since E157–E164 and E167–E172 return to a non-relativistic-like situation, it makes sense to draw d-block analogies for E165 and E166 – especially since here we again have the group IB- and IIB-like situation with a weaker shielding provided by the d-subshell, and if the gap is bigger between 7d and 9s than it was for the other d-series, well, that follows the trend that we see incipient in the 4d series. Thus it is reassuring to see that E165 and E166 continue the trend of falling ionisation energies for the non-relativistic Cu-Ag and Zn-Cd series, which had suffered an interruption at the relativistic Au-Rg and Hg-Cn.)

Note that their table 10 of predicted properties gives as the most analogous group for E157–E164 the expected IIIB through VIII, and for E167–E172 the expected IIIA through 0; we follow these, only squeezing E165 and E166 instead into the gap of IB and IIB instead of IA and IIA.

From the 1975 paper:

Again, the same table with the group assignments is given.

"In the periods before the 8th period, normally all d and p elements are influenced in their chemical behavior more or less by the outer s electrons. This is no longer true for the d transition elements 155 to 164, where the 8s and 8p_1/2 eleetrons are bound so strongly that they do not participate in the chemical bonding. Fig. 22 shows the outer electronic wave functions of element 164 with the deeply buried 8s and 8p_1/2 electrons. This electronic structure is quite similar to that of the d elements of the lower periods, where the outer s electrons are removed." (Well, in many chemical environments the configuration of such a d-element is indeed d^xs⁰! And let's not forget what I said earlier about this continuing the trend towards disfavouring s-occupancy even in the gaseous atom that we already see in the 4d series.) One might therefore argue that, as a first guess, the aqueous and ionic behavior of an E^m+2 ion of the lower d elements is comparable to an E^m ion of elements 155 to 164 after making allowance for the different ionic sizes and charge. But because the 9s and 9p_1/2 states are easily available in 164 for hybridization, the chemical behavior is expected not to be too different from that of the other d elements." (Therefore we see that we must mentally think of 9s rather than 8s as the covering s-shell here. And indeed we sometimes see promotions to there in the ground state: compare the 4d and 7d series! I here use the predictions in the table at the bottom of this article:)

4d	Y	Zr	Nb	Mo	Tc	Ru	Rh	Pd	Ag	Cd
	4d15s2	4d25s2	4d45s1	4d55s1	4d55s2	4d75s1	4d85s1	4d105s0	4d105s1	4d105s2
7d	157	158	159	160	161	162	163	164	165	166
	7d39s0	7d49s0	7d49s1	7d59s1	7d69s1	7d79s1	7d89s1	7d109s0	7d109s1	7d109s2

Eccola! And if you will see in some reputable places slightly different predictions with regard to which are 9s⁰ and 9s¹, well, that just goes to show that 7d and 9s are nearly degenerate, doesn't it? Surely it is nice to see such nearly exact homology, though! ^_^)

(This consideration is why I disagree with Fricke's argument for his placement of E165 and E166, which goes as follows:)

"From the normal continuation of the periodic table one would expect that after the completion of a d shell (at element 164) two elements in the IB and IIB chemical groups should appear. In a very formal way this is true, because with the filling of the 9s electrons in elements 165 and 166 there are outer s electrons chemically available. On the other hand, these outer s electrons should be the ones which began with the onset of the period. The 8s electrons are already very strongly bound so that the two 9s electrons which are filled in have to be assumed to define the beginning of a new period." (But as we can see, already by the time we get out of the quagmire of superactinides, it is 7d and 9s which are running the show, as if 7d was a transition series in between 9s and the hybrid 9p_1/2+8p_3/2 that are nearly degenerate and act like the 3p shell. So there is a slow transition between thinking of 8s as the outer s-shell and replacing it with 9s. Now, their comparisons of ionisation energies and atomic radii have some force. So let's draw a table:)

Li	Na	K	Rb	Cs	Fr	119	165
152	186	227	248	265	(~255?)	(240)	(210)
		Cu	Ag	Au	Rg	165
		128	144	144	(152 or 138)	(210)
Be	Mg	Ca	Sr	Ba	Ra	120	166
112	160	197	215	222	(~225?)	(200)	(180)
		Zn	Cd	Hg	Cn	166
		134	151	151	(160 or 147)	(180)

(Metallic radii are in picometres for the stable elements from Atomic radii of the elements (data page), and from Fricke for Rg, Cn, and the undiscovered ones. Figures for francium and radium are shameless WP:OR based on the covalent radius supplemented by graphomancy from Fricke's Fig. 10 in this paper, suggesting Fr is around the average of those of Rb and Cs, and Ra is a bit larger than Ba, but they are not the point anyway *handwaves*.) Double sharp (talk) 16:21, 10 August 2019 (UTC)

Can Double_sharp translate this obsolete IB/IIB/IA/IIA trash into the modern group and block notation? Incnis Mrsi (talk) 16:55, 10 August 2019 (UTC)

@Incnis Mrsi: I have added a concordance to the top of the post for the benefit of those who don't immediately understand this notation. I have not changed the main body of the comment for the most part as (1) the A and B are being used in the (old) sources which are being directly quoted and (2) the chemical meaning of the old notation is precisely what is relevant when classifying E165 and E166. The fact that it has chemical meaning incidentally makes me wonder if it's truly necessary to call it "trash": if it became so in the end, it was because no one could agree whether A/B meant "main-group/transition" (speaking loosely for group 12) or "left/right" (i.e. pre-transition and transition vs. post-transition, speaking loosely for group 11), not because neither distinction had a basis in truth. (Both agree on what IA/IB and IIA/IIB mean, which are the important ones here anyway.) Double sharp (talk) 03:20, 11 August 2019 (UTC)

Is “the hybrid 9p_1/2+8p_3/2” a quotation from Fricke? What exactly did he say about these orbitals and 9s alike? The question is somewhat related to one on talk:Valence shell‎‎ – seemingly the dogma that the valence shell is always ns ∪ np for some n is not universal. Incnis Mrsi (talk) 11:28, 19 August 2019 (UTC)

Fricke directly states that a new "subshell" comprising energetically close 9p_1/2 and 8p_3/2 appears in 167–172, noting that this creates somewhat of a non-relativistic situation but also that the close overlap (hybrid) is coincidental. (Fricke 1975 (ref 19), p. 133–134) I'm not sure if this is presented differently in other sources, however. ComplexRational (talk) 11:55, 19 August 2019 (UTC)

Is 9p_1/2 the first case where hybridization results in something like a “classical” six-states p without the spin–orbit splitting? And is the hybrid expected to actually behave like valence shells in 2 and 3? Incnis Mrsi (talk) 12:07, 19 August 2019 (UTC)

It appears that both are likely. The first six periods are known (or in the case of 7, predicted) to have only one p-subshell, with relativistic effects thereafter altering the order of filling and splitting the 8p subshell. As for chemical properties, Fricke states that the hybrid subshell will indeed bear considerable resemblance to the valence shells of periods 2 and 3. ComplexRational (talk) 12:33, 19 August 2019 (UTC)

@Incnis Mrsi: What Fricke writes is (1975): "Between 167 and 172 the 9p_1/2 and 8p_3/2 electrons will be filled, and it is quite an accident that the energy eigenvalues are so close together (see Fig. 14) that a p shell will occur containing 6 electrons with virtually no splitting of the subshells but different principal quantum numbers. This situation is analogous to the nonrelativistic p shell in the 3rd period. Therefore, the normal oxidation states of elements 167 to 170 will be 3 to 6. Element 171 is expected to have many possible oxidation states between −1 and +7, as the halogens do. Here again, the electron affinity will be high enough to form a hydrogen halide like H(171). Fricke et al. (56) calculated a value for the electron affinity of 3.0 eV, which is as high as the value of [I⁻], so that (171)⁻ will be quite a soft base. Element 172 will be a noble gas with a closed p shell outside. The ionization energy of this element, as shown in Fig. 15, is very near to the value of Xe, so that it might be quite similar to this element. The only great difference between Xe and 172 isthat element 172 is expected to be a liquid or even a solid at normal temperatures because of its large atomic weight. As indicated in connection with the noble gas 118, element 172 will tend to be a strong Lewis acid and hence compounds with F and O are expected, as has been demonstrated for xenon." About the same text appears in the 1971 paper with Waber, but then 171⁻ is compared to Cl⁻ and called a "quite a hard base" instead. In the 1971 paper with Greiner and Waber the comparison is to the 2nd as well as the 3rd periods. No, there is no explicit use of the word "hybridisation", but given the close energy eigenvalues it is pretty much inevitable (albeit it would have to involve the s-orbitals as well to get the group oxidation states for elements 167 through 172, analogous to In through Xe chemically, so perhaps it might be better to call this "spp" rather than "pp" hybridisation if we are to mention it at Orbital hybridization). Double sharp (talk) 13:53, 19 August 2019 (UTC)

(Now let's show ionisation energies, because if you've read till here you probably want me to:)

Li	Na	K	Rb	Cs	Fr	119	165
520.2	495.8	418.8	403.0	375.7	380	(462.0)	(520)
		Cu	Ag	Au	Rg	165
		745.4	731.0	890.1	(1020)	(520)
Be	Mg	Ca	Sr	Ba	Ra	120	166
899.5	737.7	589.8	549.5	502.9	509.3	(563.3)	(630)
		Zn	Cd	Hg	Cn	166
		906.4	867.8	1007.1	(1155)	(630)

(Data from molar ionisation energies of the elements and this page. Neither trend looks all that great, as both demand some sort of about-face; but if we consider Au–E120 part of the "relativistic effects zone" that should be exceptional, against the trend of the other elements, it seems to me that putting E165 and E166 in groups 11 and 12 respectively makes more sense as then the trend goes back to normal once we go into the "pretending to be out of the relativistic effects zone" that includes E157–E173. If we can stomach E119 and E120 as A-group elements with B-group tendencies, then surely we can also stomach E165 and E166 as B-group elements with A-group tendencies. The much lower density of E165 and E166 compared to E156–E164 can to some extent be considered an illustration of this.) Double sharp (talk) 16:32, 10 August 2019 (UTC)

TL;DR: the classification of E157–E164 as group 3–10 elements is supported by Nefedov et al. in their periodic table illustration, by Kul'sha's popularisation article (see the previous section), and also by Fricke's table in his papers giving assignments of what he calls groups IIIB through VIII; Fricke himself admits that this is the most chemically relevant classification with E164 as a heavy congener of Pd and Pt. The classification of E165 and E166 as B-subgroup rather than A-subgroup elements is at least partially supported by Fricke's papers as well, and is the classification used by Kul'sha (like E119 and E120, they do mix characteristics of A-subgroup and B-subgroup elements); finally E167–E172 present no problems (well, apart from us drawing them in period 8 rather than 9, but that is obvious and also what Kul'sha's article does.) Double sharp (talk) 07:35, 11 August 2019 (UTC)

Electron configuration table

We should probably add a few caveats to note that this is just one set of values; the Fricke 1975 paper contains a few differences from this set, for example. (Many electron configurations should have similar energies, making it difficult to predict which is the ground state.) It may even better to give multiple sets! Double sharp (talk) 15:09, 19 August 2019 (UTC)

That's a good idea. Some sources even give several possibilities and indicate that they are difficult to predict, such as the thesis for E123. This also reminds me of an old idea (in this old sandbox diff): perhaps we could also include Aufbau to further highlight the influence of relativistic effects on SHE properties? ComplexRational (talk) 15:46, 19 August 2019 (UTC)

Sure, Aufbau would be good to include too. It should be enough to give a pure-Aufbau extrapolation: a few authors attempted to predict minor deviations following previous periods (e.g. Chaikkorskii predicted E160 and E161 to be d⁹s¹ and d¹⁰s¹ respectively, presumably following the irregularities of Pt and Au; see table 1 of Fricke's 1975 paper, p. 98), but since we now know that the real deviations are far greater, just having pure Aufbau as a comparison should be enough. Double sharp (talk) 06:18, 21 August 2019 (UTC)

Unbitrium

Why is Unbitrium not in the article? Did someone forget to write it? UB Blacephalon (talk) 16:58, 12 December 2019 (UTC)

This is because there is not enough coverage of unbitrium specifically in reliable sources; if this were so, it would have its own article. 123 appears often, alongside other elements such as 124, in generic predictions of chemical and nuclear properties, but its synthesis has never been attempted unlike elements 119–122 and 124–127, and it has not been of historical interest as 124 and 126 have been. If and when more detailed predictions specific to 123 are made RS, its article could perhaps be written. ComplexRational (talk) 22:19, 12 December 2019 (UTC)

Alright but even in the extended periodic table it skips over 123 and goes straight to 124. Why is that? UB Blacephalon (talk) 14:08, 13 December 2019 (UTC)

The only place with such a "skip" is § Synthesis attempts. 123 is missing simply because it had no synthesis attempts. ComplexRational (talk) 15:32, 13 December 2019 (UTC)

Oh. Couldn't you put that in the article so people aren't wondering what happened to 123? Its almost like its not that important. UB Blacephalon (talk) 16:18, 13 December 2019 (UTC)

No need, it's already there at the top of § Synthesis attempts: Unsuccessful attempts have been made to synthesise the period 8 elements up to unbiseptium, except unbitrium. ComplexRational (talk) 22:12, 13 December 2019 (UTC)

Seriously broken formatting

Something is VERY wrong with this article - the ENTIRE text is just a link to https://en.wikipedia.org/wiki/Unseptbium, which then links back to this very article. It's not possible to click any other links, images or scroll sub-sections, any clicks just causes the article to reload. The affected area is limited at the top midway between the line under the title and "From Wikipedia, the free encyclopedia", at the bottom just inside the bottom of the frame around "Categories: Hypothetical chemical elements | Periodic table", and sideways between the left and right margins of the main text (so the tabs on the top, the left-hand menu and the "last edited"/copyright notice at the bottom works normally).

I tried looking at the code without finding anything obviously wrong, since I don't know the finer aspects of Wikipedia formatting I didn't dare change anything in case I just screws it up further. To me it looks like some minor typo causing it all to fall apart, like a missing closing tag, parenthesis or quote mark.

Checking the history, it seems like https://en.wikipedia.org/w/index.php?title=Extended_periodic_table&oldid=921971391 (01:49, 19 October 2019) works normally, while the following edit https://en.wikipedia.org/w/index.php?title=Extended_periodic_table&oldid=921973461 (02:08, 19 October 2019 - "Fricke model: do merge of Extended periodic table (detailed cells)") is the first broken one and should be looked into. — Preceding unsigned comment added by 88.89.69.251 (talk)

That's odd. For me, it displays just fine on desktop, mobile web, and mobile app, and nothing seems wrong with the markup. I don't quite see the problem, or any unusual links to unseptbium; could you explain it a bit more? ComplexRational (talk) 19:49, 5 April 2020 (UTC)

It may be a browser issue, the page acts up in Firefox 28.0 (with Noscript) but seems to work normally in Pale Moon 26.5.0 (Atom/XP) and Opera 36.0. Still, the way it's fine in one edit but fails in the next (plus that I don't experience anything similar in other Wikipedia articles) indicates that something may be wrong with the page.

Another (and significantly worse) thing is that this talk page seems to misbehave too - I can neither see my original comment nor your reply in any of these browsers, the page ends with the "Unbitrium" section and your "No need, it's already there..." comment from December 2019. Oddly, I can see them in History*, the edit window and and if I select "preview", but no matter what it won't show up on the actual page - I've tried clearing the cache, cold-booting the computer and resetting the network modem, to no avail. Just as I'm writing this it suddenly started showing up in Pale Moon but not the others - I really can't get the heads and tails of this. I'll try to post this reply in Pale Moon, to see if that helps.

• Note how I did several edits in a vain attempt at getting it working - including (accidently) posting and then removing a duplicate, and removing some hidden garbage characters from the History section (which I only could see because Notepad warned me about non-ANSI characters when I tried saving the draft). — Preceding unsigned comment added by 88.89.69.251 (talk) 21:35, 5 April 2020 (UTC)

Nope - it still shows up in Pale Moon but not the others, there the page ends with the Unbitrium section. While I'm used to browser incompatibilities and some pages not working in all of them, I've never seen anything like this - it's usually caused by some trash javascript or over-complex HTML5 coding, I've never seen that a section of plain text shows up in one browser but not the others. I wonder if it's a server-side issue and a misguided attempt at "adapting" the page to various browsers. — Preceding unsigned comment added by 88.89.69.251 (talk) 21:48, 5 April 2020 (UTC)

Feynmanium

Who added the name Feynmanium on element 137. feynmanium is not even the official name for 137. it is named from fandomium — Preceding unsigned comment added by 110.159.152.33 (talk • contribs)

As of this edit, the article no longer includes "feynmanium". While the edit summary called the term WP:OR, I don't think that really applies — it's right there in the source, a column by Philip Ball at Chemistry World. It is a thing people say, though there doesn't appear to be solid ground for attributing the argument to Feynman, and it's not a correct argument anyway. XOR'easter (talk) 13:03, 19 April 2020 (UTC)

If anyone has an explanation for how this argument about Z = 137 got attached to Feynman, I'd like to know. XOR'easter (talk) 14:41, 19 April 2020 (UTC)

Any interest in a "Superactinides in popular culture" section?

Science fiction author Samuel Delany's novel Nova is driven by a race to acquire fictional elements of atomic numbers in the 300s. Would this be a useful addition to the article, do you think? — Preceding unsigned comment added by 72.203.138.29 (talk) 20:28, 22 April 2020 (UTC)

Unfortunately, I'd strongly advise against including it here. Superheavy elements are described in many fictional works, and I don't believe even the most well-known ones (I can think of several in Star Trek and naqahdah from Stargate, for example) earn recognition in this article (or for that matter, any on this topic). If you believe this is a specifically noteworthy appearance, maybe it could be added to List of fictional elements; this article describes chemical, nuclear, and physical aspects and is not meant to harbor indiscriminate fictional references (even if sourced). I'm sorry. ComplexRational (talk) 21:57, 22 April 2020 (UTC)

Not to mention that elements with atomic numbers in the 300s would not be superactinides, and in fact current serious predictions of chemical properties don't even reach 200. Double sharp (talk) 03:50, 23 April 2020 (UTC)

Nefedov

Would it be illustrative to add the Nefedov PT to the article? {{Extended periodic table (by Nefedov, 54 columns, compact cells)}} -DePiep (talk) 16:21, 23 January 2021 (UTC)

Number of superactinides

This says:

The superactinides may be considered to range from elements 121 through 157, which can be classified as the 5g and 6f elements of the eighth period, together with the first 7d element.

This would make only 33 elements, not 37, because a g-orbital can hold up to 18 electrons. Please fix this statement. Georgia guy (talk) 12:46, 24 January 2021 (UTC)

It's not a mistake. While a simple look at the orbitals (Aufbau principle) would indeed suggest that there are 33 superactinides, overlapping orbitals caused by relativistic effects consistently (in RS) predict the 7d series as 157–166 and the 8p series as 167–172. This follows also from a breakdown of the Aufbau principle and leaves 37 predicted superactinides. Could this concept be presented more clearly? ComplexRational (talk) 13:23, 24 January 2021 (UTC)

Which extension theory covers this? In the TOC are: § Aufbau model, § Pyykkö model, and § Fricke model. Also {{Nefedov et. al.}} is mentioned, but to me unclear where to put this one (Aufbau calculations?). -DePiep (talk) 14:03, 24 January 2021 (UTC)

It is a distinct one from all those – calculation results are similar to Fricke, but interpretations of what it means for PT placement differ. In any case the thing is rather most clearly expressed in one place by Kulsha anyway in his popular-science article (although this predates him switching to the superwide form that more clearly expresses how the g elements fit): Nefedov et al. is rather terse and still has a Sc-Y-* group 3. Anyway the whole thing is kind of dependent on the state of the art of calculations (so, it may still change in future). Double sharp (talk) 14:59, 24 January 2021 (UTC)

Are some of them 5g, some 6f, and some 8p1/2?? If so, please fix the description. Georgia guy (talk) 16:04, 24 January 2021 (UTC)

Pyykkö tried to formally assign such. But the mixing is so much that your question does not really correspond to any real division. Double sharp (talk) 17:11, 24 January 2021 (UTC)

Don't we help the articles (and so ourselves) when we add info with every theory like (1) note whether Z is increasing; (2) how the known 7-period PT fits/non-fits above the period 8+ extension? I mean to say, if the extensions forces a new structure (for example, cannot-be-made-with-increasing-Z), then these are new features. Should stop me thinking in old Group/Period/Block concepts then. -DePiep (talk) 21:20, 24 January 2021 (UTC)

Pyykkö's extension violates the increasing Z. Nobody else's does. But then again, nobody actually knows for sure what is going on because really complete calculations have not yet been done beyond the very start of the 5g elements. Even in this "nicest" and most chemically sound format of Kulsha we have 22 5g elements instead of the expected 18, which violates in some way the IUPAC desiderata for group 3. But again it is hard to say what exactly 5g and 6f elements are there, due to all the mixing: this is just a natural generalisation, in which 5g means "there is some use of the 5g subshell chemically", and 6f means "there is some use of 6f and none of 5g". FWIW Scerri (chair of that IUPAC project) wrote "Now even if elements with atomic numbers as high as 139 and 140 were ever to materialize, one can still ask whether such unexpected orderings or violations of the Madelung rule should be reflected in any modified periodic table. After all, there are many violations of the Madelung rule such as the 20 well-known anomalous configurations beginning with chromium and copper which do not lead us to modify the periodic table". OTOH there is also the point that somehow it is elements 157–172 that are chemically and electronically exact analogues of Y–Xe in groups 3–18, not 153–168, and somehow one needs to deal with this extra four because 8s and 8p_1/2 are drowned into the core. So one should somehow take everything here beyond maybe E123 as tentative. Double sharp (talk) 02:53, 25 January 2021 (UTC)

It's confusing...

...that the table of electron configurations jumps from 173 to 184. Georgia guy (talk) 12:13, 18 February 2021 (UTC)

No investigations have been done yet for the ones in between, so there'd be nothing to write. But added a row with ellipses, to avoid people "correcting" it. Double sharp (talk) 13:14, 18 February 2021 (UTC)

(P.S. And frankly don't hold your breath for elements beyond early 120s.) Double sharp (talk) 17:05, 27 March 2021 (UTC)