Which of the following has more number of unpaired d-electrons ?

Options

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

Answer

B

Explanation

`Zn^(+) (Z = 30) implies [Ar] 3d^(10) implies` zero unpaired d electrons.
`Fe^(2+) (Z = 26) implies [Ar] 3d^(6) implies 4` unpaired d electrons.
`Ni^(2+) (Z = 28) implies [Ar] 3d^(8) implies 2` unpaired d electrons.
`Cu^(+) (Z = 29) implies [Ar] 3d^(10) implies` zero unpaired d electrons.