Question

Which of the following has the maximum number of unpaired electrons?

• A. $M{g}^{2+}$
• B. $T{i}^{1+}$
• C. $V^{3+}$
• D. $F{e}^{2+}$

Answer 1

The correct option is D $F{e}^{2+}$

Let us compare the electronic configuration of these elements:
$M{g}^{2+}:1s^{2}2s^{2}2p^6$: no unpaired electron.
$T{i}^{3+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^1$: one unpaired electron.
$V^{3+}:1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^2$: two unpaired electrons.
$F{e}^{2+}:1s^{2}2s^{2}2p^{6}3s^{2}s{p}^{6}3d^6$: four unpaired electrons
Thus, we see that $F{e}^{2+}$ has the most unpaired electrons.