Question

The magnetic moment of a compound of transition element is 3.9 B.M. Write the number of unpaired electrons in the element.

Answer 1

Magnetic moment of any compound is given by
µ = (\sqrt { n(n+2) })
Where n is the no. of unpaired electrons.
So,
3.9 = (\sqrt { n(n+2) })
Squaring both side
15.21 = n2 + 2n … (1)
This equation (1) satisfying for n = 3. So no. of unpaired electrons in this elements will be three.