Question

Which of the following presents the correct order of second ionization enthalpies of C, N, O and F?

• A. F > O > N > C
• B. O > N > F > C
• C. C > N > O > F
• D. O > F > N > C

Answer 1

Answer: (D)

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 $O^{+}$ has highest second ionisation enthalpy than $F^{+}$ and $N^{+}$
$\therefore$ correct order is O > F > N > C