Which change(s) in electron structure occur when 1 $Mn$ atom is converted to a $M{n}^{2+}$ ion in the 111 phase?

(P) The number of occupied energy levels decreases.

(Q) The number of half-filled orbitals decreases.

Electron structure occur when 1 $Mn$ atom is converted to a $M{n}^{2+}$ ion in the 111 phase, The number of occupied energy levels decreases.

When the two electrons are added in the $Mn$ in that condition, the electrons get filled into the 3d5 orbital, Due to which the number of occupied energy level decreases.

$M{n}_{25}\to \left[As\right] 3d^{5}4s^2$

The electronic configuration of $Mn$ is

$M{n}^{+2}\to 3d^5$

Hence, the number of occupied energy level decreases.

Therefore, option A is correct.