Question

Consider the hydrates ions of $Ti^{2+}, V^{2+}, Ti^{3+}$ and $Sc^{3+}$. The correct order of their spin-only magnetic moments is :

• A. $Sc^{3+} < Ti^{3+} < Ti^{2+} < V^{2+}$
• B. $ Ti^{3+} < Ti^{2+} < Sc^{3+} < V^{2+}$
• C. $Sc^{3+} < Ti^{3+} < V^{2+}< Ti^{2+}$
• D. $V^{2+} < Ti^{2+} < Ti^{3+} < Sc^{3+ }$

Answer 1

Answer: (A)

$Ti^{+2} = 1s^2 \; 2s^2 \; 2p^6 \; 3s^2 \; 3p^6 \; 3d^2$
unpaired electrons = $2$.
spin only magnetic moment $(\mu) = \sqrt{2(2+2)}$
$ = \sqrt{8} $ B.M
$Ti^{+3} = 1s^2 \; 2s^2 \; 2p^6 \; 3s^2 \; 3p^6 \; 3d^1$
unpaired electrons = 1
$\mu = \sqrt{1(1+2)} = \sqrt{3}$ B.M
$V^{+2} = 1s^2 \; 2s^2 \; 2p^6 \; 3s^2 \; 3p^6 \; 3d^3$
$\mu = \sqrt{3(3+2)} = \sqrt{15} $ B.M
$Sc^{+3} = 1s^2 \; 2s^2 \; 2p^6 \; 3s^2 \; 3p^6$
$\mu = 0 $