Electron configuration and half-filled shells

[studyq]

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I know that Chromium and some other elements with d electrons rearrange their configuration to achieve a half-filled or fully filled shell. For example Chromium is [Ar]3d5 4s1 instead of the expected [Ar]3d4 4s2 because the d shell is half filled which has additional stability.

Does this only occur with d elements? For example Carbon is [He]2s2 2p2 instead of [He]2s1 2p3 which would have a half filled p orbital.

Thanks

 

[sillyjoe]

For the MCAT this only occurs in the D shell with either half (5 e-) or full (10e-). Remember you move only one electron. Never more.

 

[Saxappeal1]

^^ sillyjoe has a point, that rule works, but generally they just want you to know that the weird exception is Cr