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+)` `4.87` B.M. because….

Explanation

Magnetic moment of any metal ion can be decided on the basis of spin as well as orbital contribution of electron. Due to symmetrical electronic configuration, there is no orbital contribution in `Cr^(3+)` ion. However, appreciable orbital contribution takes place in `Co^(2+)` ion.