Talk:Flerovium/GA1

GA Review

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Reviewer: Protonk (talk · contribs) 18:40, 11 September 2014 (UTC)[reply]

overview

At first glance the article looks great. It's clear and well sourced with a good flow to it. I'm struggling to find major problems. :)

The only major(ish) problem I san see (and I'm not sure how to fix it) is that the history of both the nuclear and chemical experiments are not as contextualized as I'd like. We get a blow by blow for each, noting theory, discovery and conflicting results followed by some measure of confirmation for one set of results. But we don't get much of a retrospective for either. Do we have an explanation (other than the emminently possible "physics is tricky") for why we saw these conflicting results? Are they common when dealing with synthesis and detection of super heavy elements? Was failure to replicate early experiments a source of frustration or doubt?

It's quite common for superheavy elements for this sort of thing to happen in early experiments. It's usually not until quite some time after the experiments that we can look in retrospect and realize what happened. Even now, we only have a clear idea what happened for ²⁸⁷Fl. One confirmed isotope is enough to say you have a new element, so IUPAC accepted the discovery claim for element 114. But we still don't know exactly what was going on for the other four claimed isotopes. Double sharp (talk) 04:30, 12 September 2014 (UTC)[reply]

Apologies in advance for not properly styling element/isotope annotations in this review. Also "nuclei" no longer looks like a word to me. Send help.

content

In Discovery we note that the 1998 experiment was not repeated, then later in Road to confirmation we see that a 1999 experiment produced Fl-288, later confirmed to be Fl-289. Does this count as a repitition or are we specifically saying that the decay chain observed in 1998 has not been observed again?
- Sorry, that was my poor prose – the latter is correct. The experiment was repeated, but the decay chain observed in 1998 was never seen again. Hopefully I've explained it better now. Double sharp (talk) 04:30, 12 September 2014 (UTC)[reply]
"This therefore implied the de facto discovery of flerovium, from the acknowledgment of the data for the synthesis of Fl-287 and Lv-291" It's not obvious to me why the discovery of copernicum represents an acknoledgment of flerovium's existence.
- Added a few words to explain why – it's because the isotopes ²⁸⁷Fl and ²⁹¹Lv decay to ²⁸³Cn. IUPAC accepted the discovery of the nuclide ²⁸³Cn, invoking the flerovium and livermorium data, which thus implied that Fl and Lv were also discovered. Double sharp (talk) 04:30, 12 September 2014 (UTC)[reply]
"However, in 1966, new predictions arrived that expected the next proton shell to occur instead at element 114, and that the stabilization would make nuclides in this region as stable against spontaneous fission as many stable heavy nuclei such as lead-208" What was different about these predictions? It may be too detailed for this article, but we do spend some time on the oblateness of nuclei when talking about the predictive value of the nuclear shell model. Is a digression here of similar value to the article?
- Well, the difference was that they were actually predictions, instead of calculations specifically chosen to produce Z = 126 (which was suggested because N = 126 is known to be a closed neutron shell). From the cite I just added to explain this in the article: "It was no mere chance that parameters of the widely known Nilsson scheme constructed on the oscillatory potential were more often fitted so as to reproduce the shell Z = 126 in the region of large A, i.e. the prediction was in fact substituted by the assumption of the Nilsson scheme being valid for the description of a system of SHN levels. However, as early as in the midsixties when interest in the problem revived, some theoreticians understood that the oscillatory potential (the Nilsson scheme) is not valid for this purpose.". The SO and potential interactions are different in this region and you cannot just assume that they are the same – doing so gives you Z = 126. Double sharp (talk) 05:21, 12 September 2014 (UTC)[reply]
"Due to the expected high fission barriers, any nucleus within this island of stability exclusively decays by alpha decay..." I'm not clear on the relationship between this sentence and the one which precedes it. Some isotopes near the island of stability may decay in such a way that they become more stable, but such decay is extremely unlikely? Is that the gist?
- You are almost right! The electron capture is needed to actually reach the stable island but may or may not happen. The alpha decay would approach the stable island but would not get on to it and the decay chain would terminate with spontaneous fission after passing close to but not reaching the island. Double sharp (talk) 04:56, 12 September 2014 (UTC)[reply]
When we have a compound nucleus (e.g. Pu-244 + Ca-48) experiments show that such nuclei decay by releasing magic nuclei. So far so good. Is there a reason why we note that one such nucleus is doubly magic? Are they more likely to expel doubly magic nuclei? Below (when talking about quasifission) we note that some nuclei are likely to expel doubly magic nuclei, not just magic ones. Are we talking about a similar process and if so should the first sentence just note doubly magic nuclei?
- Yup, it was a repetition. It is a similar process and now I've combined the two paragraphs and removed the mention of singly magic nuclei (the only common one that appears as a product is ²⁰⁹Bi, which is just one proton past being doubly magic anyway). Double sharp (talk) 04:37, 12 September 2014 (UTC)[reply]
"Earlier predictions stated the melting and boiling points of flerovium to be around 70 °C and 150 °C...", later in the same sentence "...the boiling point was also predicted to be ~1000 °C or 2840 °C in earlier studies" We should call one set "earlier studies" and use some means to disambiguate between the two. Why the divergence?
- OK, now calling the high values earlier studies. (Actually they were roughly contemporary, but the lower values became the accepted ones.) The group predicted the lower values noted that a dramatic decrease in sublimation enthalpy was expected between E113 and Fl on the basis of group trends, which in turn would imply a low boiling point: and this would support the inertness of the quasi-closed shell electron configuration of flerovium. This is now in the article. Double sharp (talk) 04:47, 12 September 2014 (UTC)[reply]
" the 2010 study suggested again a noble-gas-like character, but the complete set taken together resulted in a more ambiguous interpretation." How so?
- Clarified. Double sharp (talk) 05:22, 12 September 2014 (UTC)[reply]

style/layout

Lede looks good.
A lot of terms are overlinked (e.g. proton, neutron)
- Removed the duplicate links. I did leave one to radon, though, as the first time it was mentioned only by its atomic number 86. Double sharp (talk) 07:10, 12 September 2014 (UTC)[reply]
Instead of saying "(see below)", should we link to a section name containing the information?
- This seems to be a remnant of an old version of the article, when some extra material from isotopes of flerovium was in a section below. Now that it's been moved into its own subarticle, though, the "(see below)" no longer makes sense, and I've removed it. The info is above anyway. Double sharp (talk) 05:32, 12 September 2014 (UTC)[reply]
"Currently, possibilities for the synthesis of the expected long-lived nuclei of copernicium..." This is a really long sentence. I suggest severing the last clause (about controlled nuclear explosions) into a new one as it is basically a complete thought by itself.
- Done Double sharp (talk) 04:39, 12 September 2014 (UTC)[reply]
Maybe this is a lack of familiarity w/ the Physics style guide, but I think we should wikilink to Oxidation state before introducing notation like lead(II). We only wikilink it in the infobox, nowhere in prose.
- Oh dear, did I forget to link it ALL the time despite mentioning the term a lot? Yes, I did! *facepalm* Remedied. Double sharp (talk) 05:07, 12 September 2014 (UTC)[reply]
The periodic table of videos is in the sources and in the external links. Is it a common fixture for external links in element articles or should that link be removed?
- Link removed (along with WebElements, which for this element doesn't really say anything we don't already). Double sharp (talk) 05:28, 12 September 2014 (UTC)[reply]
Is it common practice in physics articles to refer to different studies in success by year rather than by the authors name? E.g. we have a lot of text like "the 2010 study" or "the 2009 experiments". In some cases many appear to have been done in the same lab and have multiple co-authors, so a pithy pointer may not be forthcoming, but is it worth naming some that we return to multiple times?
- Yes, I realized this problem and tried to name the main characters involved. Mostly it's the FLNR/JINR in Russia, the PSI in Switzerland, and the GSI in Germany. As you say, they were mostly done in the same labs, so to disambiguate I chose to reference the dates instead. Double sharp (talk) 05:03, 12 September 2014 (UTC)[reply]

Again, overall I don't see any real show stoppers. Assuming some of the above questions can be addressed I can pass this in short order. Protonk (talk) 23:59, 11 September 2014 (UTC)[reply]