Use Hund’s rule to derive the electronic configuration of

Ce : $1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{10} 5 s^{2} 5 p^{6} 4 f^{1} 5 d^{1} 6 s^{2}$

Magnetic moment can be calculated as:

$\mu=\sqrt{n(n+2)}$

Where,

n = number of unpaired electrons

The electronic configuration of Ce3+ : 1s22s22p63s23p63d104s24p64d105s25p64f1

In Ce3+, n = 1

$\therefore \mu=\sqrt{1(1+2)}=\sqrt{3}=1.732$ B. $\mathrm{M}$