Although `Cr^(3+) and Co^(2+)` ions have same number of unpaired electrons but the magnetic moment of `Cr^(3+)` is 3.87 B.M and that of `Co^(2+)` is 4.87 B.M. Why?

Explanation

In `Cr^(3+)` there is no orbital contribution because of symmetrical configuration while in `Co^(2+)`, the orbital contribution is present significantly