Which of the following should be the order of increasing values of second ionisation potential of `C_(6),N_(7),O_(8)` and `F_(9)`

Options

A. `C gt N gt F gt O`
B. `C lt F lt N lt O`
C. `C lt F lt N lt O`
D. `C lt N lt F lt O`

Answer

D

Explanation

The second ionisation potential means removal of electron from a cation
`C^(+1) (5e) = 1s^(2),2s^(2),2p^(1)`
`N^(+1) (6e) = 1s^(2),2s^(2),2p^(2)`
`O^(+1) (7e) = 1s^(2),2s^(2),2p^(3)`
`F^(+1) (8e) = 1s^(2), 2s^(2), 2p^(4)`
Therefore `C lt N lt F lt O`