Which one of the following ions has electronic configuration `[Ar]3d^(6)` ? `(At. Nos. Mn = 25, Fe = 26, Co = 27, Ni = 28)`

Options

A. `Ni^(3+)`
B. `Mn^(3+)`
C. `Fe^(3+)`
D. `Co^(3+)`

Answer

D

Explanation

`Ni^(3+)(28)=[Ar]3d^(7)`
`Mn^(3+)(25)=[Ar]3d^(4)`
`Fe^(3+)(26) = [Ar]3d^(5)`
`Co^(3+)(27)=[Ar]3d^(6)`
Hence, `Co^(3+)` has `3d^(6)` electronic configuration correct answer is (d).