Question

Magnetic moment $2.83BM$ is given by which of the following ions? (At. no. $Ti=22,Cr=24,Mn=25,Ni=28$ )

• A. $T{i}^{3+}$
• B. $N{i}^{2+}$
• C. $C{r}^{3+}$
• D. $M{n}^{2+}$

Answer 1

Answer: (B)

Magnetic moment is given by $\mu =\sqrt{n(n+2)}$
Here, $n=$ number of unpaired electrons
$\Rightarrow 2.83=\sqrt{n(n+2)}$
$\Rightarrow (2.83{)}^2=n(n+2)$
$\Rightarrow 8.00=n^2+2n$
$\Rightarrow n^2+2n-8=0$
$\Rightarrow n^2+4n-2n-8=0$
$\Rightarrow (n+4)(n-2)=0$
$\therefore n=2[\because n\ne -4]$
Among the given ions:
Hence, $N{i}^{2+}$ possesses a magnetic moment of $2.83BM$.