Question

The magnetic moment of a transition metal compound has been calculated to be $3.87$ B.M. The metal ion is

• A. $T_1^{2+}$
• B. $Mn ^{2+}$
• C. $V ^{2+}$
• D. $Cr ^{2+}$

Answer 1

Answer: (C)

$ Cr ^{+2}:[ Ar ], 3 d ^4, 4 s ^0 n =4, \mu=\sqrt{4(4+2)}=\sqrt{24} $
$ =4.89\, BM $
$ Mn ^{+2}:[ Ar ], 3 d ^5, 4 s ^0 n =5, \mu=\sqrt{5(5+2)}=\sqrt{35} $
$ =5.91 \,BM $
$V ^{+2}:[ Ar ], 3 d ^3, 4 s ^0 n =3, \mu=\sqrt{3(3+2)}=\sqrt{15} $
$=3.87 \,BM $
$ Ti ^{+2}:[ Ar ], 3 d ^2, 4 s ^0 n =2, \mu=\sqrt{2(2+2)}=\sqrt{8} $
$ =2.82 \,BM $