Which has the stable electronic configuration : `Ni^(2+)orFe^(+3)`. Why ?

Explanation

`Ni^(2+)[Ar]3d^(8)`
`Fe^(3+)[Ar]3d^(5)`
Half filled and completely filled orbitals are more stable compared to partially filled orbitals . Therefore `Fe^(3+)` is more stable compared to `Ni^(2+)`.