Which of the following lanthanoid ions is diamagnetic ?
(At nos . `Ce = 58 , Sm = 62, Eu = 63 , Yb =70)

Options

A. `Sm^(2+)`
B. `Eu^(2+)`
C. `Yb^(2+)`
D. `Ce^(2+)`

Answer

B

Explanation

lectronic configuration of the given species are
`a. Sm^(2+) ( Z=62) = [Xe] 4f^(6) b.Eu^(2+) (Z=63) = [Xe] 4f^(7)`
c . `Yb^(2+) (Z=70) = [Xe] 4f^(14) d. Ce^(2+)( Z =58) = [Xe] 4f^(1) 5d^(1)`
On the basis of above electronic configuration, only `Yb^(2+)` (Z=70 ) has no unpaired electrons i.e. has fully-filled orbitals. Thus it is dimagnetic in nature.