Which one of the following has maximum number of unpaired electrons

Options

A. `Mg^(2+)`
B. `Ti^(3+)`
C. `V^(3+)`
D. `Fe^(2+)`

Answer

D

Explanation

`Mg^(2+) = 10` electron, `1s^2 2s^2 p^6` - No unpaired electron
`Ti^(3+) = 19` electron, `1s^2 2s^2 p^6 3s^2 p^6 3d^1` - One unpaired electrons
`V^(3+) = 20` electron, `1s^2 2s^2 p^6 3s^2 p^6 3d^2` - two unpaired electrons
`Fe^(2+) = 24` electron, `1s^2 2s^2 p^6 3s^2 p^6 3d^6` - Four unpaired electrons.