The correct order of second ionization potential of carbon, nitrogen, oxygen and fluorine is:-
The correct option is
O > F > N > C
Electronic configuration of element after removal of first electron
Second Period: C N O F
The second ionization potential of oxygen is more, as it acquires a half-filled stable electronic configuration so it requires a lot of energy to remove electrons from the oxygen. Hence it has the highest ionization energy.
So, the correct order of second ionization potential is O > F > N > C.