Talk:Valence electron

old comments

This article seems full of misinformation, for instance "Every atom is much more stable, or less reactive, with a full valence shell," well what about Na? It will be in the form of an ion is it has a full shell, Na+, which is not stable at all. This holds for most atoms. And what about "As a general rule, the fewer electrons in an atom's valence shell, the more reactive it is." Fluorine is an extremely (probably one of the most) reactive atom. Theres other errors as well, and I picked these with my huge chemistry knowlege of the first semester of CHEM101. Someone out there must be a chemist or summit like that so please correct this page because I don't have the required knowlege or understanding of chem to do so my self. --LeakeyJee 09:03, 12 June 2006 (UTC)

The stated general rule pertaining to relative reactivity.

"As a general rule, the fewer electrons in an atom's valence shell, the more reactive it is."

This is only true for metals, non metals behave differently, the more e^- a nonmetal has the more reactive it is. Fluorine (F), a 7A element is the most electronegative and the most reactive element. F can be bonded to noble gases. —The preceding unsigned comment was added by 72.242.4.11 (talk) 12:51, 8 February 2007 (UTC).

As the comments above indicate, this article is awful! It's better not to have an article at all rather than a misleading one. I'm proposing it for deletion. I've fixed up "Electron shells" somewhat, which covers some of the same ground, and propose a redirect to that article. This one should be re-created when there is too much ***accurate*** information to fit in Electron Shells. Umptious (talk) 17:09, 27 March 2008 (UTC)

I have today removed (finally) the statement that "As a general rule, the fewer electrons in an atom's valence shell, the more reactive it is", as well as a similar statment in the intro. I have made clear that this is only true for metal atoms. There is more work to do, but I think we are now on the right track. Dirac66 (talk) 22:00, 30 March 2009 (UTC)

Suggestions for expanding and improving the article.

I think an additional image needs to be added to this article displaying an atom with more shells. As the term valence shell refers to the outermost shell of an atom. The current picture of the Helium atom might not be sufficient to convey that principle, as Helium only has one shell, which is at the same time its valence shell. So i propose a secondary image of an atom which contains more shells and with a description under it like the one under the Helium atom image. Formankind, May 8th 2008. —Preceding comment was added at 03:21, 8 May 2008 (UTC)

Connection between valence electrons and Active Orbitals?

Quantum chemists please see: http://en.wikipedia.org/wiki/N-electron_valence_state_perturbation_theory and associated talk page. — Preceding unsigned comment added by 2.123.253.142 (talk) 17:50, 14 January 2012 (UTC)

Transition metal valence electrons...

the simple table in Valence electron does exclude helieum as an exception in group18, however referring to List_of_elements_by_atomic_properties there are a few more exceptions (denoted by the message in *), G5: Niobium, G6: Chromium, Molybdenum, G7: Technetium, G8: Ruthenium, G9:Rhodium, G10: Platinum, G11: Copper, silver, gold. All these have one instead of two. Charlieb000 (talk) 01:15, 10 January 2014 (UTC)

Metal that is either conductive or malleable but not both?

According to the section Electrical conductivity, "a metal is an element with high electrical conductivity or malleability when in the solid state." But is there any metal that is malleable but not electrically conductive? And are there metals that are electrically conductive but not malleable? If the answer is no to both those questions, that "or" should probably be changed to an "and", right? Is there any solid at all that is either conductive or malleable but not both? —Kri (talk) 13:57, 24 June 2017 (UTC)

The sentence now in the article is somewhat misleading, because metals are defined by their place in the periodic table and not by their properties. As a rule, metals have high conductivity and malleability, but these are not defining properties. Also, this section is about conductivity, so the mention of malleability is confusing and I will delete it. Dirac66 (talk) 12:09, 2 July 2017 (UTC)

P orbitals in transition metals, lanthanides and actinides

I see that @Sandbh: does not consider the np orbitals to be valence orbitals in d-block and f-block. However, don't they appear in transition metal complexes and actinide complexes (maybe not so much lanthanide complexes)? I.e. they are not occupied in the neutral atom but they are in molecules.--Officer781 (talk) 23:37, 18 September 2020 (UTC)

Officer781: This is getting complicated. The article is about valence electrons. np electrons are not valence electrons in d- and f-block elements. Otherwise vacant np orbitals may well be used in complexes, however. Sandbh (talk) 00:08, 19 September 2020 (UTC)

@Sandbh: Yes, so that is why it is mentioned that these refer to the orbitals not the electrons. I placed a second row to refer to the orbitals in complexes, hopefully that is better? What do you suggest?--Officer781 (talk) 00:12, 19 September 2020 (UTC)

It's tricky. Let me get back to you on that one. Meanwhile, more below. Quick response is to focus on getting valence electrons right, first. That is hard enough. Then, look at the question of the add ons like valence orbitals, which adds another layer of complexity. Sandbh (talk) 00:19, 19 September 2020 (UTC)

Even if one wants to go for "electrons" rather than "orbitals", Lr still needs 7p inclusion because of its ground-state configuration [Rn]5f¹⁴6d⁰7s²7p¹. Double sharp (talk) 18:54, 5 November 2022 (UTC)

Valence electrons in lanthanides

Officer781: Associated with all of this, for example, lanthanides do not have from 3 to 16 valence electrons. Most of them are d¹s² i.e. three valence electrons. Only cerium, praseodymium, neodymium, terbium, and dysprosium can access one f-electron apiece, up to two for Pr(V). Sandbh (talk) 00:19, 19 September 2020 (UTC)

@Sandbh: That has a rather different reason of contracted orbitals though (it's spatial accessibility rather than energetic accessibility, they are inaccessible due to repulsion of the occupied outer electrons), which also happens but to a more limited extent for first row transition metals (they use more s-character in molecules than subsequent rows). Some lanthanide complexes do have accessible f orbitals as seen recently from literature (but these are I admit harder to come by but they do occur). So this is tricky as well.--Officer781 (talk) 00:29, 19 September 2020 (UTC)

@Sandbh: I think the fundamental difference in our thinking is that I tend to think of molecules first but you tend to think of ions first. But I think the molecules have to be covered in this article (at the very least the orbitals) section as well. That would make f orbitals more firmly valence in lanthanides. Unless we can think of an alternative. We can't be counting only the ionizable electrons because that neglects the molecules. An example is copper for transition metals which has at most two ionizable electrons but the others are accessible in molecules. Same goes for gold with three ionizable electrons. If we only count ionizable electrons we can't compare between rows.--Officer781 (talk) 00:32, 19 September 2020 (UTC)

Valence matters generally

Officer781: I just had a look at four chemistry dictionaries and none have an entry for valence orbital.

Only two define valence electron/s:

1. "The electrons in the outermost shell of an atom determining chemical properties."
2. "An electron in one of the outer shells of an atom that takes part in forming chemical bonds."

For #1 I can see F has seven valence electrons. For #2, F has just one valence electron; O has just two. Ne has none.

In contrast, all four dictionaries have entries for metalloid/s.

My one physics dictionary gives the same definition of a valence electron as #2.

Nothing of the above matters so much, as long as whatever terminology used is clearly defined.

I supposed a chemically active electron = a valence electron, which occupies a valence orbital. Does that mean that an empty orbital which accepts electrons donated by a ligand is chemically active = a valence shell? Sandbh (talk) 01:22, 19 September 2020 (UTC)

@Sandbh: I would point out that the word used here is chemical bond which also includes covalent bonds. And covalent bonds use more electrons than what is ionizable. For instance, d8 gold complexes use four electrons for the square planar shape, whereas gold can only ionize 3 electrons. So chemical bond does not count just ionic bonds or oxidation state but also covalent bonds. I tend to agree with the view that if it accepts electrons it is a valence orbital (certainly thats the view of the computational chemists). Maybe we need sources.--Officer781 (talk) 02:13, 19 September 2020 (UTC)

I mean, computational chemists agree that as long as it can accept electrons it is a valence orbital. What is ambiguous is what do you count as valence orbital for the atom or ion itself? I would think those additional orbitals are not valence orbitals in those cases but they are in molecules and complexes.--Officer781 (talk) 02:17, 19 September 2020 (UTC)

@Sandbh: I reordered the sections so that valence electrons are introduced only in their atomic state. Then, valence shell is introduced so that chemical reactions can be discussed. So here, there is a clear progression from atoms to molecules. Hopefully this is better?--Officer781 (talk) 02:27, 19 September 2020 (UTC)

Officer781: I'll have a look. One thing: the block-based focus is good. So e.g. the d-block e.g. is groups 3-12, with group 3 showing not much characteristic TM chemistry and group 12 showing effectively none. Sandbh (talk) 03:11, 19 September 2020 (UTC)

Yes, we do need sources

To repeat the last sentence of the 4th last comment above: "Maybe we need sources." At the moment the whole article contains 15K bytes and exactly 4 citations, all in the Overview section. The References list has 6 items, but nos. 5 and 6 are explanatory footnotes, not sources. If there are good sources (textbooks, review articles, good web pages) for the statements in the rest of the article, then we need to find and include some. If sources of similar reliability contradict each other on some points (as I suspect from the above discussion), then we are allowed to fall back on "Some authors say X, but others say Y" (while identifying the sources of course); this is what is meant by WP:NPOV. And if there are some points for which there don't seem to be any sources, then those points should be deleted; if not then they could be considered original research which should not be in Wikipedia per WP:NOR. Of course applying these policies in practice requires some judgment, but overall I think there is a serious lack of sources in this article. There are other articles on chemical bonding which are much better sourced. Dirac66 (talk) 22:27, 20 September 2020 (UTC)

Minor confusion on ranges

Based on enumerating and the values given in the table, I infer that the correct way of applying this to transition metals and lanthanides/actinides is that:

• Scandium, Yttrium, Lanthanum, Actinium have 3
• Cerium and Thorium have 3
• Praseodymium and Protactinium have 4
• ...
• Ytterbium and Nobelium have 15
• Lutetium and Lawrencium have 16
• Titanium, Zirconium, Hafnium, Rutherfordium have 4
• Vanadium, Niobium, Tantalum, Dubnium have 5
• ...
• Copper, Silver, Gold, Roentgenium have 11
• Zinc, Cadmium, Mercury, Copernicium have 12

But it would be nice to have confirmation or explanation that this is wrong in the article. Especially since it seems off for the first two lanthanide/actinide groups to repeat "3" even if that is actually consistent with the periodic table arrangement as shown in the image!

I found this source but the values it provides for the p-block are different than the article.

--RProgrammer (talk) 23:55, 1 November 2020 (UTC)

This is another case of the group 3 problem, because Lu and Lr don't have (n−2)f as valence shells. But now it shows Sc-Y-Lu-Lr, so it's correct (La-Ac 3, Ce-Th, 4, ..., Yb-No 16; Sc-Y-Lu-Lr 3, Ti-Zr-Hf-Rf 4, ..., Zn-Cd-Hg-Cn 12). Double sharp (talk) 18:53, 5 November 2022 (UTC)

valance shell for s block elements include p subshell, could be amended to just s subshell, or clarified

I notice that the table has 4 columns. "helium and hydrogen", "s and p blocks", "d block", "f block"

I spoke to some chemists and they agreed re the "helium and hydrogen" column.

But took issue with "s and p blocks" being combined, since they said they don't have the same valence shell.

p does indeed have the valence shell of ns and np, which the table says (n being period number).

But (most) s block elements only have the valence shell ns. To have ns and np is more of an exception. Beryllium has a valence shell of ns and np via covalent bonding and SP Hybridisation.

So wouldn't it be much better if the table had s,p,d,f columns.. and showed the valence shell for each eg ns for the s block. ns and np for the p block . e.t.c. And noting that it's not without exception, mentioning the exception of Beryllium (and apparently Magnesium in a Grignard reaction), which have ns and np in theier valence shell.

One person suggested to me that maybe the author of that table had in mind that s block elements might potentially be in an excited state. But that could apply to other elements in other blocks too, e.g. chlorine in the p block, it could have an electron in the f subshell if in an excited state. And also, an excited element in the s block might have an electron in a subshell beyond np e.g. in (n+1)s. So it'd be a very flawed table if it's trying to include showing the valence shell in excited states. But no doubt it has ns np because of the SP Hybridisation of eg Beryllium.

What are molecules?

I think i want help with that 41.115.27.54 (talk) 18:59, 8 February 2023 (UTC)

A valid question. I have now added a link to the article on Molecule at the first appearance of the word in this article, so readers can click on the link and find a definition and discussion. Dirac66 (talk) 20:14, 8 February 2023 (UTC)

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