How many valence electrons does Cr have?

1 Answer
Jun 28, 2017

Answer:

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

Explanation:

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..."#