Which transition metals have #3d^5# in their valence electron configurations?

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Answer 1 · 2018-02-07T01:29:24

Manganese AND chromium have valence electron configurations that have #3d^5#. They are:

#[Ar] 3d^5 4s^2#, for manganese
#[Ar] 3d^5 4s^1#, for chromium

Chromium is what we call an "aufbau" exception, i.e. the order of orbital filling seems to contradict filling by lowest energy first.

And for these #3d# orbitals, #n = 3, l = 2#.

The #m_l# for all the #d# orbitals lie in the range from #-l# to #l#, so...

#m_l = -2,-1,0,1,2#

And the spins of all of them are in a half-filled #3d# subshell, which means they must be all spin up, #m_s = +1/2#.

Therefore, the combinations are simply

#(n,l,m_l,m_s) = (3,2,{-2,-1,0,1,2}, +1/2)#

And the electrons look like:

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