Answer 1

The electronic configuratioon of Mn⁺² ion is [Ar]3d⁵4s⁰

It has five unpaired electrons in its d-orbitals which is maximum value for a transition metal ion. While Mn⁺³ ion has electronic configuration [Ar] 3d⁴ 4s⁰.

Mn⁺² ions are more stable than Mn⁺³ ions.