Talk:Helium

Covalent radius

How does the concept of covalent radius make sense for helium, as it doesn't normally bond with anything? If it is based on a measurement of a bond in some actual helium compound, what is the compound? It seems like a reference is needed in the infobox.CountMacula (talk) 15:59, 8 November 2022 (UTC)

Hmm. In Covalent radius it says: Tabulated values of covalent radii are either average or idealized values, which nevertheless show a certain transferability between different situations, which makes them useful. I suspect the idealized values part allows it. Note that on Covalent radius it has two (very) different values for helium. I suspect that not putting one on this page would be a good choice. Gah4 (talk) 18:30, 8 November 2022 (UTC)

There are known bound ions containing helium, see Helium compounds#Known ions. I don't think it's too much of a stretch to consider HeH⁺ to contain a H–He covalent bond, so these values make sense even without idealisation. The bigger problem to my mind is that the two values are very different, as Gah4 says. Double sharp (talk) 17:00, 29 December 2023 (UTC)

Semi-protected edit request on 6 September 2023

Where they say that large amounts of helium-4 are made in stars, add to it "and a little more from alpha decaying radioactive materials" or some variation thereof. RealNamesAreFineZ.E.O (talk) 17:06, 6 September 2023 (UTC)

 Not done: please provide reliable sources that support the change you want to be made. M.Bitton (talk) 21:44, 6 September 2023 (UTC)

Featured Article status

This very early FA needs improvement to keep its status; it has had two cleanup banners for years now, on citations and updates. The latter is especially troubling, with sentences such as "is expected to be largely depleted by 2021" and a lack of updates for issues such as conservation, the potential new molecular compounds, and applications usage. I will list this on WP:FARGIVEN, in case anyone wants to take it to FAR. ~~ AirshipJungleman29 (talk) 13:34, 25 March 2024 (UTC)

@AirshipJungleman29: I see that the clean-up banners are still on the page. Would you be interested in evaluating the article to see if the banners should be removed, or do you want to nominate this to WP:FAR? Z1720 (talk) 22:52, 26 May 2024 (UTC)

Isn't Helium p-block element

Many resources consider helium as p block element as it behaves like noble gas AdiDas5501 (talk) 13:55, 9 May 2024 (UTC)

It is classified as an s block element because the last shell that is filled is the 1s shell. –LaundryPizza03 (dc̄) 04:52, 12 May 2024 (UTC)

The classification into blocks is based on electron configurations, rather than chemical behaviour (except to the extent that the former relates to the latter). Double sharp (talk) 03:46, 23 September 2024 (UTC)

As far as I know, there is no consensus on the lanthanides and actinides being 0 to 13, or 1 to 14, f-electrons. Given that, is it obvious that p-block means 1 to 6, and not 0 to 5, p-electrons? CS people like to start counting at zero, but maybe chemists start at 1. Gah4 (talk) 00:43, 24 September 2024 (UTC)

The logic behind those (like me) who consider the f-block to start at La and Ac is not that we start at 0, but that La and Ac are really f¹ elements who just happen to have an anomalous configuration in the atom (kind of like Cu d¹⁰s¹ instead of d⁹s²), but who can correct that in chemical compounds (e.g. LaF₃ has noticeable 4f valence contributions). In the other blocks, even that's not a problem. So both sides are counting from 1, and just disagree on what counts as 1.

In any case, if you wanted to count from 0–5 for some reason, the noble gases would all be s⁰ and hence s-block. I've not seen that idea since it became clear that noble gases do have (np) chemistry, though. Double sharp (talk) 02:49, 24 September 2024 (UTC)

Yes, at higher Z the rules are less obvious. The differences in energy levels are not so big. Well, that also gives the varying valence for transition metals. But the more usual question, is how to draw a nice periodic table. Which elements go in the rows below. And reminds me, it seems that there is question about Og being a noble gas or not. Gah4 (talk) 20:28, 24 September 2024 (UTC)

Normally the PT just gets drawn according to idealised valence configurations (i.e. assuming that the Aufbau held perfectly to Z = 118). Since this is always an excited state within the range of chemical bond energies, it tends to work fine (I don't know if it will be so past about 121, though). Exceptions sometimes happen for La and Ac (due to a long string of copying from when lanthanoid electron configurations were first wrongly thought to be 4f^0-145d¹6s² in general, rather than exceptionally; it was difficult in the 1920s and 1930s); and He (an almost universal exception, because hardly anybody likes putting helium with alkaline earths).

Og is not a noble gas in the sense that it's expected not to be particularly noble and might not be a gas at STP (if you could ever make enough and have it somehow not decay instantly). It is one in the sense that it's expected to be 7s²7p⁶, making it formally fit group 18 even though its chemistry probably has more to do with Ge or Sn. But in general the issue for Cn through Og is that while the electron configurations formally fit Hg to Rn, the massive energy gap between 7p_1/2 and 7p_3/2 results in qualitatively different behaviour. Double sharp (talk) 03:18, 25 September 2024 (UTC)

By the way, would a split of energy level also occur eventually for d or f orbitals? If yes, it becomes significant from which principal quantum number? 129.104.65.7 (talk) 06:16, 26 September 2024 (UTC)

It already occurs in the known elements, but even at 5f and 6d it doesn't seem to create a qualitative change. Those series split more naturally into halves (7+7 and 5+5) than into 6+8 and 4+6. I don't think there are any good enough calculations of the 6f and 7d regions. :( Double sharp (talk) 06:32, 26 September 2024 (UTC)

OK, what a pity. :( 129.104.65.7 (talk) 07:29, 26 September 2024 (UTC)

By the way, putting He in p-block is one of the biggest mistakes that has persisted in my country's chemistry textbooks for decades ... 129.104.241.231 (talk) 22:40, 24 September 2024 (UTC)

Janssen not co-discoverer

The helium article should be edited in several places to correct the history of the observation of the line near D3. "Helium was first detected as an unknown, yellow spectral line signature in sunlight during a solar eclipse in 1868 by Georges Rayet,[14] Captain C. T. Haig,[15] Norman R. Pogson,[16] and Lieutenant John Herschel,[17] and was subsequently confirmed by French astronomer Jules Janssen.[18] Janssen is often jointly credited with detecting the element, along with Norman Lockyer. Janssen recorded the helium spectral line during the solar eclipse of 1868, while Lockyer observed it from Britain. "

This text is almost entirely wrong and needs to be rewritten. Rayet's report in no way can be interpreted to conclude that he saw a new line near the D line; see the quotation given. Haig's report is relatively vague, and the colors given do not correspond to that of the D3 line (which is yellow). Pogson's unpublished report is ambiguous and non-quantitative; he could not rule out that the line he saw was the D line itself. And Herschel concluded that the line he saw WAS the D line, not a new line. Ascribing any portion of the discovery of the line Lockyer called D3 is wishful thinking. F

Also, the following sentences should be removed: "The line was detected by French astronomer Jules Janssen during a total solar eclipse in Guntur, India.[26][27] This line was initially assumed to be sodium. " Janssen did NOT report this line in his 1868 letter to the French Academy, and the cited references (Kochhar and Emsley) do not provide compelling evidence to the contrary. For better references, which conclude that Janssen did not see this line before Lockyer, see Launay F (2008) The astronomer Jules Janssen—a globetrotter of celestial physics. Springer, New York, p 45 and Lockyer JN (1868) Spectroscopic observations of the sun—No. II. Phil Trans Roy Soc (London) 159:425–444 as well as the footnote in the Wikipedia text that begins "In his initial report to the French Academy of Sciences" — Preceding unsigned comment added by 65.141.64.252 (talk) 15:38, 9 June 2024 (UTC)