Question

Why is Mn²⁺ ion more stable than Fe²⁺ ion?

(Atomic numbers of Mn = 25 and Fe = 26)

Answer 1

Electronic configuration of Mn²⁺ = [Ar]4s⁰3d⁵ and Fe²⁺ = [Ar]4s⁰3d⁶

Mn²⁺ ions have half-filled d-orbitals, making them more stable. Fe²⁺ complexes are slightly less stable since their third orbital contains six electrons.

As a result, they frequently achieve a stable 3d⁵ structure while losing one electron (from Fe³⁺).