Question

find out magnetic moment of an element having two unpaired electrons in B.M

Answer 1

The magnetic moment of a transition metal ion is

15

BM. Therefore, the number of unpaired electrons present in it is 3.

If n is the number of unpaired electrons, then the magnetic moment is given by the expression:

μ=

n(n+2)

15

=

n(n+2)

15=n(n+2)

15=n

2

+2n

n

2

+2n−15=0

This is the quadratic equation with solution

n=

2a

−b±

b

2

−4ac

n=

2(1)

−2±

2

2

−4(1)(−15)

n=

2(1)

−2±8

n=3 or n=−5.

The negative value is discarded as the number of unpaired electrons cannot be negative.

Hence, n=3 .