Question

Why is mn2+ more stable than mn3+​

Answer 1

See Explanation

Step-by-step explanation:

Let us closely consider the electronic configuration of manganese atom, Manganese II ion and manganese III ion. This will give a clue of the answer.

Manganese: [Ar] 3d5 4s2

Manganese II: [Ar] 3d5

Manganese III: [Ar] 3d4

Now, let us remember that the d orbital contains a maximum of ten electrons. Hence, the electronic configuration of Mn^2+, [Ar] 3d5 reflects a half filled d- orbital which is known to be unusually stable(half-filled orbitals are known to possess unusual stability just as fully filled orbitals do).

The same can not be said about Mn^3+. Hence, Mn^2+ is more stable than Mn^3+.