Question

Arrange the following metal complex/compounds in the increasing order of spin only magnetic moment. Presume all the three are high spin system.
$\left(1\right)\left(N{H}_4{)}_2\right[Ce\left(N{O}_3{)}_6\right]$
$\left(2\right)Gd(N{O}_3{)}_3$ and
$\left(3\right)Eu(N{O}_3{)}_3$
(Atomic numbers $Ce=58,Gd=64\text{and}Eu=63)$

• A. $\left(1\right)<\left(3\right)<\left(2\right)$
• B. $\left(1\right)<\left(2\right)<\left(3\right)$
• C. $\left(3\right)<\left(1\right)<\left(2\right)$
• D. $\left(2\right)<\left(1\right)<\left(3\right)$

Answer 1

The correct option is A $\left(1\right)<\left(3\right)<\left(2\right)$

More the number of unpaired electrons $\left(n\right)$ on the central metal ion, more is the magnetic moment.

$\left(N{H}_4{)}_2\right[Ce\left(N{O}_3{)}_6\right](n=0)\Rightarrow \mu =0BM$
$Eu\left(N{O}_3{)}_3\right(n=6)\Rightarrow \mu \approx 6.9BM$
$Gd\left(N{O}_3{)}_3\right(n=7)\Rightarrow \mu \approx 7.9BM$