How do you write the electron configuration for #Ni^(+2)#?
More correctly the electrons lost are the
When Nickel becomes
The 4s electrons a lower energy level that the 3d electrons because of the simpler electron path of the S orbital. So in the ground state the electrons being lost should be the 3d electrons.
However the 4s electrons are further from the nucleus so losing the the 2 4s electrons leaves only the third shell electrons making the atoms more stable than losing the 3d electrons.
So the somewhat stable electron configuration of
Electron configuration for Ni is
So when writing electron configuration for
I suggest to watch Tyler DeWitt's YouTube video on electron configuration. It helped me a lot.