Use Hund's rule to derive the electronic configuration of `Ce^(3+)` ion, and calculate its magnetic moment on the basis of spin-only formula.

Explanation

`Ce(Z = 58) : [Xe]^(54) 4f^(1) 5d^(1) 6s^2`
`Ce^(3+) = 4f^1`
No. of unpaired electrons = 1
`mu_s = sqrt(n (n+2)) = sqrt( 1 ( 1+2)) = sqrt3 = 1.73 B.M. `