Which one of the following has the least magnetic moment ?

Options

A. `Cu^(2+)`
B. `Ni^(2+)`
C. `Co^(2+)`
D. `Fe^(2+)`

Answer

A

Explanation

`Cu^(2+) to [Ar] 4s^0 3d^9` , only one unpaired `e^-` in 3d orbital