- A $\mathrm { C } > \mathrm { N } > \mathrm { O } > \mathrm { F }$
- B $\mathrm { O } > \mathrm { N } > \mathrm { F } > \mathrm { C }$
- C $\mathrm { O } > \mathrm { F } > \mathrm { N } > \mathrm { C }$
- D $\mathrm { F } > \mathrm { o } > \mathrm { N } > \mathrm { C }$
Show answer & explanation
Correct answer: C
N$^{+}$ : 1s$^{2}$2s$^{2}$2p$^{2}$
O$^{+}$ : 1s$^{2}$2s$^{2}$2p$^{3}$
F$^{+}$ : 1s$^{2}$2s$^{2}$2p$^{4}$
Generally, IE$_{2}$ increase along a period but IE$_{2}$ of O+ is more than F+ due to extra half filled p subshell.
Therefore, option (3) is the correct answer.