Q17 / 75 · JEE Main 2026 (22 January Shift 2) · Chemistry

Given below are two statements :
Statement I: $\quad \mathrm{C}<\mathrm{O}<\mathrm{N}<\mathrm{F}$ is the correct order in terms of first ionization enthalpy values.
Statement II: $\quad \mathrm{S}>\mathrm{Se}>\mathrm{Te}>\mathrm{Po}>\mathrm{O}$ is the correct order in terms of the magnitude of electron gain enthalpy values.
In the light of the above statements, choose the correct answer from the options given below :

  • A
    Statement I is true but Statement II is false
  • B
    Statement I is false but Statement II is true
  • C
    Both Statement I and Statement II are false
  • Correct answer
    D
    Both Statement I and Statement II are true

Solution

Statement I:
Ionization enthalpy generally increases across a period from left to right.
However, Nitrogen ($2s^2 2p^3$) has a stable half-filled electronic configuration, making it harder to remove an electron compared to Oxygen ($2s^2 2p^4$).
Thus, the order is $C < O < N < F$.
Statement I is true.

Statement II:
For Group 16 elements, Oxygen has an exceptionally low magnitude of electron gain enthalpy due to its small size and high inter-electronic repulsions in the $2p$ subshell.
The magnitude of electron gain enthalpy decreases down the group from Sulphur onwards.
The correct order of magnitude is $S > Se > Te > Po > O$.
Statement II is true.

Both statements are correct.

Hence, the correct answer is option: 'D'.

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