`Mn^(2+)` compounds are stable but `Fe^(2+)` compounds are susceptible to + 3 oxidation state. Explain.

Explanation

`Mn^(2+)` has a stable half-filled configuration `(3d^(5)4s^(0))` and hence removal of electron from `Mn^(2+)` requires very high energy. On the contrary to this, `Fe^(2+)` has an electronic configuration of `3d^(6)4s^(0)`. Hence `Fe^(2+)` undergoes oxidation to form stable `Fe^(3+)` ion with stable `3d^(5)` configuration.