Chemistry - PERIODIC TABLE Question with Solution | TestHub

In a period the value of ionisation potential increases from left to right with breaks where the atoms have some what stable configuration. After removing an $e^{-}$ oxygen will acquire stable configuration. Hence ${\mathrm{O}}^{+}$has highest second ionisation enthalpy than ${\mathrm{F}}^{+}$and ${\mathrm{N}}^{+}$. $\therefore$ correct order is $\mathrm{O}>\mathrm{F}>\mathrm{N}>\mathrm{C}$