Question

The correct order of ionization enthalpy is

• A. C < B < O < N
• B. B < O < C < N
• C. N < C < O < B
• D. B < C < O < N
• E. C < B < O < N

Hint:

Ionization enthalpy generally increases across a period due to increased nuclear charge, but decreases down a group due to increased atomic size and shielding effects.

Answer 1

The Correct Option is D

Ionization enthalpy is the energy required to remove an electron from an atom in the gaseous state. The trend in ionization enthalpy follows the atomic structure and the number of protons in the nucleus.
- B < C: Boron (B) has a lower ionization enthalpy than Carbon (C) because it has a single electron in the 2p orbital, which is easier to remove compared to the 2p orbital in carbon.
- C < O: Oxygen (O) has a higher ionization enthalpy than carbon due to increased effective nuclear charge and a smaller atomic radius, which makes it harder to remove an electron.
- O < N: Nitrogen (N) has a higher ionization enthalpy than oxygen due to its stable half-filled 2p orbitals (which provides extra stability).
Thus, the correct order of ionization enthalpy is (D) B < C < O < N.