Question

Magnetic moment 2.83 BM is given by which of the following ions? (At. no. Ti =22, Cr=24, M n=25, N i=28)

• A. $Ti^{3+}$
• B. $Ni^{2+}$
• C. $Cr^{3+}$
• D. $Mn^{2+}$

Answer 1

Answer: (B)

$Ni^{2+}$

Answer 2

Magnetic moment is given by $\mu = \sqrt {n(n+2)}$ Here, n = number of unpaired electrons \Rightarrow \hspace5mm 2.83=\sqrt {n(n+2)} \Rightarrow \hspace5mm (2.83)^2=n(n+2) \Rightarrow \hspace5mm 8.00=n^2+2n \Rightarrow \hspace5mm n^2+2n-8=0 \Rightarrow \hspace5mm n^2+4n-2n-8=0 \Rightarrow \hspace5mm (n+4)(n-2)=0 \therefore \hspace15mm n=2 \hspace5mm [\because n \ne -4] Among the given ions: Hence, $Ni^{2+}$ possesses a magnetic moment of 2.83BM.