The correct order of the second ionisation potential of carbon, nitrogen, oxygen and fluorine is

Options

A. `CgtNgtOgtF`
B. `OgtNgtFgtC`
C. `OgtFgtNgtC`
D. `FgtOgtNgtC`

Answer

C

Explanation

`C(6) 1s^(2)2s^(2) 2p_(x)^(1) 2p_(y)^(1)" " N(7) 1s^(2)2s^(2)2p_(x)^(1) 2p_(y)^(1) 2p_(z)^(1)`
`O(8) 1s^(2)2s^(2)2p_(x)^(2) 2p_(y)^(1)2p_(z)^(1) " " F(9)1s^(2)2s^(2)2p_(x)^(2)2p_(y)^(2)2p_(z)^(1)`
O has highest `2^(nd)` ionization potential i.e., ionization energy because after losing one electron, it acquires stable half filled p-electronic configuration.
F is smaller than N, therefore, it has higher second ionization potential. C has least due to bigger size.