Which of the following has the maximum number of unpaired d-electron?

Options

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

Answer

B

Explanation

`._30Zn[Ar]6(18)3d^(10),So n=0,Fe^(2+)[Ar]^(10)3d^(6)`,so `n=4,Ni^(2+)[Ar]^(18)3d^(8),So n=2,Cu^(2+)[Ar]^(18)3d^(5)4s^(2)`.