Which of the following shows maximum magnetic moment?&

More be the number of unpaired electrons → more be the magnetic moment.

and

Number of unpaired electrons in ${Mg}^{2 +} = 0$

Number of unpaired electrons in ${Ti}^{3 +} = 1$

Number of unpaired electrons in $V^{3 +} = 2$

${Fe}^{2 +} = 4$

Number of unpaired electrons in

Thus, ${Fe}^{2 +}$ show maximum value of magnetic moment $( \mu )$.

also, $\mu = \sqrt{n ( n + 2 )}$. $BM$ (n =$Number of unpaired electrons).</p>$