Arrange `Ce^(3+),La^(3+), Pm^(3)` and `Yb^(3+)` in increasing order of their size -

Options

A. `Yb^(3+) lt Pm^(3+) lt Ce^(3+) lt La^(3+)`
B. `Ce^(3+) lt Yb^(3+) lt Pm^(3+) lt La^(3+)`
C. `Yb^(3+) lt Pm^(3+) lt La^(3+) lt Ce^(3+)`
D. `Pm^(3+) lt La^(3+) lt Ce^(3+) lt Yb^(3+)`

Answer

A

Explanation

According to their positions in the periodic table, these values are in the order:
`{:(,Yb^(3+),lt,Pm^(3+), lt,Ce^(3+),lt ,La^(3+)),(" At. Nos.",70,,61,,58,,57):}`