Which of the following lanthanoid ions is diamagnetic? (Atomic number of `Ce=58,Sm=62,Eu=63,Yb=70`]

Options

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

Answer

C

Explanation

Diamagnetic specied contains no unpaired electrons:
`Ce: [Xe] 4f^(1)5d^(1) 6s^(2)rArr Ce^(2+: [Xe]4f^(1)5d^(1)`, two unpaired eletrons
`Sm: [Xe] 4f^(6) 6s^(2) rArr Sm^(2+):[Xe] 4f^(6)`[ six unpaired electrons
`Eu: [Xe] 4f^(7) 6s^(2) rArr Eu^(2+): [Xe] 4f^(7)`, seven unpaired electrons
`Yb:[Xe] 4f^(14) 6s^(2) rArr Yb^(2+):[Xe]4f^(14)`, zero unpiared electrons
Thus, `Yb^(2+)` ion is diamagnetic.