Talk:Inert pair effect

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Contents 1 Electron remains in s-orbital? 2 WikiProjects 3 WikiProject class rating 4 rewrite- sorry

[edit] Electron remains in s-orbital?

I've removed the following section because it's unsourced and contradicts my understanding of the inert pair effect:

The inert pair effect can explain why Thallium forms Tl₂O while aluminium in the same group forms Al₂O₃.In aluminium, the electronic configuration is [Ne]3s² 3p_x¹. Because of the screening effect of the 2p electrons, one of the 3s electron can be excited easily to the 3p_y orbital. So Al mostly exhibits a valency of 3. However in case of Tl, the electronic configuration is [Xe]4f¹⁴ 5d¹⁰ 6s² 6p_x¹. Due to the poor screening effect of the 5d orbital, the effective nuclear charge on the 6s electron is high. Hence it cannot be excited to the 6p_y orbital. So the only unpaired electron remains in the 6p_x orbital. Hence Thallium exhibits a valency of 1 and forms Tl₂O. Similar effect is observed in tin and lead.

"Inert pairs" are stereochemically active so it doesn't make sense to me that they'd simply remain within a perfectly spherical orbital. I'm no expert on this so I could be wrong but the section could do with some rewriting anyway. Blackthirteen 00:01, 5 July 2007 (UTC)

The paragraph is wrong, but not for the reason you think it is: if the paragraph were correct, gallium would show a very strong inert pair effect, whereas it shows none at all. The correct explanation involves the effects of special relativity on the mass of the electron: for atoms with a very high nuclear charge, the s-electrons are travelling so fast near the nucleus that the reletivistic increase in mass is non-negligeable, which causes the s-orbitals to shrink and the ionization energy of s-electrons to increase. Physchim62 (talk) 01:02, 2 August 2007 (UTC)

[edit] WikiProjects

Shouldn't this also be a part of Wikiproject: Chemistry? Or is there such a thing? RobertAustin 17:32, 26 November 2006 (UTC)

Done. Physchim62 (talk) 01:02, 2 August 2007 (UTC)

[edit] WikiProject class rating

This article was automatically assessed because at least one WikiProject had rated the article as stub, and the rating on other projects was brought up to Stub class. BetacommandBot 09:54, 10 November 2007 (UTC)

[edit] rewrite- sorry

I initially tried a simple expansion but I have ended up with a complete rewrite. I hope no-one is offended. The only questions I have now is why this topic was ever categorised as a relativistic effect--yes Rel effects matter for the heaviest members but looking at the IPs it is obvious that the inert pair effect is not due to higher energy s electrons. Sadly for us all the name is a misnomer--Sidgwick started it in 1927--great man that he was - but he got this one wrong! In terms of the evolution of chemistry the term inert pair effect is probably best viewed as a vestige left over from a palaeolithic past, a bit like the human appendix. sadly for student chemists the simple explanation of the effect is still being taught, so if anyone gets low marks for quoting this article I'm sorry! Axiosaurus (talk) 18:13, 9 January 2008 (UTC)