Why are `Mn^(2+)` compounds more stable than `Fe^(2+)` toward oxidation to their `+3` state?

Explanation

Electronic configuration of `Mn^(2+)` is `[Ar]^(18) 3d^(5)`.
Electronic configuration of `Fe^(2+)` is `[Ar]^(18) 3d^(6)`
It is known that half-filled and fully-filled orbitals are more stable. Therefore, Mn in (+2) state has a stable `d^(5)` configuration. This is the reason `Mn^(2+)` shows resistance to oxidation to `Mn^(3+)`. Also, `Fe^(2+)` has `3d^(6)` configuration and by losing one electron, its configuration changes to a more stable`3d^(5)` configuration. Therefore, `Fe^(2+)` easily gets oxidized to `Fe^(+3)` oxidation state.