How many unpaired electrons are present in ferrous ion? Calculate its net spin and magnetic moment.

Explanation

Electronic configuration of `Fe^(2+)` ion is `[Ar]3d^(6)`. It has 4 unpaired electrons.
Net electron spin `= 4 xx 1//2 = 2`.
Magnetic moment, `mu = sqrt(4(4+2)) = 4.95 BM`