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In sci.physics, stefjnoskynov
<miamail@fatticazzituoi.it>
wrote
on Sat, 18 Jun 2005 20:06:35 GMT
<MPG.1d1e79b3a02a02919897f7@powernews.inwind.it>:
what's the meaning of 2P, 2D and 4S?
These are quantum nomenclatures for electron energy levels,
or "shells".
For example, helium has two 1s electrons (each shell has an
even number of states as an electron can either have half-spin
up, or half-spin down). Ergo, 1s^2.
Neon has the state structure 1s^2 2s^2 2p^6.
Argon has 1s^2 2s^2 2p^6 3s^2 3p^6; you may also see
[Ne] 3s^2 3p^6 in the literature.
I'll have to look up the exact QM parameters but basically,
the left 1,2,3 refers to one parameter, the s, p, d, and f
refers to another parameter, and finally the exponent refers to
variation of a third parameter, including a half-spin flip.
http://www.webelements.com/
contains among many other things the elctron configurations.
Above 3 the energy levels get a little weird. The 2 4s orbitals
have less energy than the 10 3d orbitals, for example -- scandium
through zinc. Iron in particular has 4 unpaired electrons in
its 3d orbitals; chromium has *every* electron (5) unpaired in
its 3d orbitals, plus an unpaired 4s electron.
--
#191,
It's still legal to go .sigless.
.
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