Cu2+ configuration

[Artin Allahverdian 2H]

Can someone please explain why the electron configuration for Cu2+ is [Ar]3d^9 and not [Ar]3d^8 4s^1? Thanks!

[Becky Belisle 1A]

It is easier to remove the outermost electrons, which are the ones in 4s.

[Imelda Mena 3I]

Yea! It is easier to remove the electrons that are on the outer shell. I think it helps if you start with the electron configuration of Cu first which from lecture we know it is one of the special exceptions as (Cu): [Ar] 3d^104s^1. From there you can see that the electron configuration for the ion Cu2+ would be 3d^9 because copper has lost 2 electrons, one is taken away from the s-orbital first and then you move on to take away another one from the d-orbital. Just remember that you always want to remove electrons from the outer shells first when you have a cation (positively charged ion). Hope this helps!