Screening effect is not observed in :

Options

A. `He^(+)`
B. `Li^(2+)`
C. `Be^(3+)`
D. in all the three

Answer

D

Explanation

All the three ions i.e., `He^(+) (1s^(1)) ,Li^(2+) (1s^(1) ) . Be^(3+)`
`(1s^(1))` have no electrons in the inner shells and hence screening effect is not observed.