The correct order of the number of unpaired electrons in the ions `Cu^(2+), Ni^(2+), Fe^(3+)`, and `Cr^(3+)`is

Options

A. `Cu^(2+) gt Ni^(2+) gt Cr^(3+) gt Fe^(3+)`
B. `Ni^(2+) gt Cu^(2+) gt Fe^(3+) gt Cr^(3+)`
C. `Fe^(3+) gt Cr^(3+) gt Ni^(2+) gt Cu^(2+)`
D. `Cr^(3+) gt Fe^(3+) gt gt Ni^(2+) gt Cu^(2+)`

Answer

C

Explanation

`Fe^(3+)-3d^5` No.of unpaired electrons = 5
`Cr^(3+)-3d^3` No. of unpaired electrons = 3
`Ni^(2+)-3d^8` No. of unpaired electrons = 2
`Cu^(2+)-3d^9` No. of unpaired electrons = 1