question_answer

The magnetic moment of \[{{M}^{x+}}\] (atomic number = 25) is \[\sqrt{15}\]BM. Then, the oxidation number \[x\] of M is

A) 3                                             

B) 4

C) 2                                             

D) 1

Correct Answer: B

Solution :

The electronic configuration of \[{{M}^{x+}}(Z=25)\]is \[1{{s}^{2}},2{{s}^{2}},2{{p}^{6}},3{{s}^{2}},3{{p}^{6}},3{{d}^{5}},4{{s}^{2}}\] Magnetic moment \[=\sqrt{n(n+2)}BM\] \[=\sqrt{5(5+2)}BM=\sqrt{35}BM\] Given, magnetic moment \[=\sqrt{15}BM=\sqrt{3(3+2)}BM\] Hence, unpaired  electrons =3 \[\therefore \]The oxidation number \[x\] is 4.