What is the electronic configuration of the first row transition metals and their dications? Why is the configuration of #Cr^(2+)# unusual?

1 Answer
anor277
Aug 20, 2017

From the #4s# subshell........#a.#

Explanation:

The atomic configuration of the first row transition series is....:

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

The ionic configuration of the #M^(2+)# cation is (usually)........

#[1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^n]^(2+)#

The #4s# electrons are conceived to be removed FIRST upon ionization. And for the explanation, you will have to consult your text. Note that the #3d# and #4s# electrons are very close in energy, and their relative energies may change upon ionization.

#Cr^(2+)# is a notable exception in that its #3d^(5)4s^1# possesses maximum multiplicity with respect to spin quantum number. Anyway, please consult your text.

Related questions
See all questions in Electron Configuration
Impact of this question
4769 views around the world
You can reuse this answer
Creative Commons License