Question

The species which contains the maximum number of unpaired electrons is:

• A. $C{o}^{3+}$
• B. $C{o}^{2+}$
• C. $F{e}^{2+}$
• D. $F{e}^{3+}$

Answer 1

Answer: (D)

$F{e}^{3+}$

The electronic configuration of the $Fe$ is $\left[Ar\right]3d^{6}4s^2$

In $F{e}^{3+}$ form, its electronic configuration can be given as follow:

$\left[Ar\right]3d^5$

Thus, it has 5 unpaired electrons.

All other species contain less than 5 unpaired electrons.

Thus $F{e}^{3+}$ is the correct answer.