Which of the following gaseous ions contains maximum number of unpaired electrons?

Options

A. `Fe^(2+)`
B. `Co^(3+)`
C. `Co^(2+)`
D. `Fe^(3+)`

Answer

D

Explanation

`Fe^(2+) (Z= 26) to [Ar]3d^(6):4` 4 unpaired electrons
`Co^(3+)(Z=27) to [Ar]3d^(6)` : 4 unpaired electrons
`Co^(2+)(Z= 27) to [Ar]3d^(7): ` 3 unpaired electrons
`Fe^(3+)(Z= 26) to [Ar] 3d^(5):` 5 unpaired electrons