Question

The ratio of magnetic moments of Fe(III) and Co(II) is
(a) 7 : 3 (b) 3 : 7
(c) √7 : √3 (d) √3 : √7

Answer 1

The ratio of magnetic moment of Fe³⁺ :  Co²⁺ is √7 : √3

Explanation:

Magnetic moment = √n(n+2)    

n = number of unpaired electrons

Now we will calculate the number of unpaired electrons.

Fe³⁺ = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁵      n = 5

Co²⁺ =  [Ar] 4s⁰ 3d⁷    n = 3

Now we will calculate the magnetic moment.

For Fe³⁺:

√n(n+2)    

√5(5+2)  

√35

For Co²⁺ :

√n(n+2)    

√3(3+2)  

√15

So the ratio of magnetic moment of  Fe³⁺ :  Co²⁺ is √7 : √3