How many valence electrons does Cr have?

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Answer 1 · 2017-06-28T04:52:04

Surely there are 6..........?

Chromium lies in Group 6 of the Periodic Table; i.e. there are 6 valence electrons.......

Given #Cr#, #Z=24#, we could write the #"d-electron configuration"# as follows......

#1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(4)#

At undergraduate level you learn that the electron configuration is actually........

#1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(1)3d^(5)#

(the half-filled #4s# and #3d# orbitals lend an extra stability!)

But in either configuration there #"SIX VALENCE ELECTRONS..."#