Question

Amongst the following ions which one has the highest magnetic moment value?

[At. no. $Co=27,Ni=28]$.

• A. $\left[Co\right(N{H}_3{)}_6{]}^{3+}$
• B. $[Co{F}_6{]}^{3-}$
• C. $[NiC{l}_4{]}^{2-}$
• D. $\left[Ni\right(CN{)}_4{]}^{2-}$
• E. $\left[Ni\right(CO{)}_4]$

Answer 1

Answer: (B)

$[Co{F}_6{]}^{3-}$

Ion/species	Number of unpaired electrons
$\left[Co\right(N{H}_3{)}_6{]}^{3+}$	$0$
$[Co{F}_6{]}^{3-}$	$4$
$[NiC{l}_4{]}^{2-}$	$2$
$\left[Ni\right(CN{)}_4{]}^{2-}$	$0$
$\left[Ni\right(C{O}_4\left)\right]$	$0$

$\because$ Magnetic moment, $\mu =\sqrt{n(n+2)}$

$\therefore [Co{F}_6{]}^{3-}$ ion has the highest value for the magnetic moment.

Hence, option $B$ is correct.