Question

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

• A. $Mg^{2+}$
• B. $Ti^{3+}$
• C. $V^{3+}$
• D. $Fe^{2+}$

Answer 1

Answer: (D)

$Fe^{2+}$

Answer 2

$Mg^{2+}=1s^2 \, 2s^2 \, 2p^6$ no unpaired electron
$Ti^{3+}= 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^1$ one unpaired electron
$V^{3+}= 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^2$ two unpaired electrons
$Fe^{2+}= 1s^2 \, 2s^2 \, 2p^6 \, 3s^2 \, 3p^6 \, 3d^6$ four unpaired electrons