Copper ion electron structure

[Rebecca Altshuler 1D]

Cu2+ ends up having the electron structure [Ar] 3d9. Why would this be, since filling the d orbital in this way does not result in a fully filled d orbital? Why is the structure not [Ar]3d7 4s2?

[904936893]

Once there is an electron in the 3d orbital, it has a lower energy than the 4s orbital, meaning that the electron configuration would be written as 3d1 4s2. Copper's neutral state electron configuration is 3d10 4s1. Since electrons are removed from the highest energy level first, the electron in the 4s1 state would be removed, and then one more from the 3d10 state, to make Cu2+.

[Archana Biju 1G]

Cu's ground state is [Ar]3d104s1 because of the exception, and so for cu^2+ you would take away the last two electrons giving you [Ar]3d9.

[005113695]

"Cu2+ ends up having the electron structure [Ar] 3d9. Why would this be, since filling the d orbital in this way does not result in a fully filled d orbital? Why is the structure not [Ar]3d7 4s2?"

One easier way to figure it out is by first using the ground state configuration:

Cu: [Ar] 3d10 4s1
And since it is asking for Cu2+, you remove the outermost two electrons

Cu2+: [Ar]3d9