Question

Explain why:
$M{n}^{2+}$ is more stable than $F{e}^{2+}$ towards oxidation to +3 state.
(At. no. of Mn = 25, Fe = 26)

Answer 1

Ground state electronic configuration of Mn is $4s^{2}3d^5$. Electronic configuration of $M{n}^{2+}$is $3d^5$ and is a half-filled configuration that impart it high stability than $M{n}^{3+}$ with $3d^4$ configuration.

Similarly, the ground state electronic configuration of Fe is $4s^{2}3d^6$ and $F{e}^{2+}$is $3d^6$ whereas $F{e}^{3+}$ is $3d^5$. Later is an half-filled configuration that impart it higher stability than $F{e}^{2+}$.

Therefore, $M{n}^{2+}$ is more stable than $F{e}^{2+}$ towards $+3$ oxidation state.