Periodic Table — Easy JEE chemistry MCQ
**[JEE Mains 2026]** Four elements from the second period (Boron to Oxygen) have the following first ionization energy values (in kJ/mol): 1086.5, 800.6, 1313.9, 1402.3. What is the first ionization energy value for Nitrogen?
- A. 1086.5 kJ/mol
- B. 800.6 kJ/mol
- C. 1313.9 kJ/mol
- D. 1402.3 kJ/mol
Solution
Order of IE₁ in 2nd period: B < C < N (anomaly due to half-filled 2p) < O (lower due to pairing) < F.
B = 800.6, C = 1086.5, O = 1313.9, N = 1402.3 kJ/mol.
Nitrogen has higher IE than oxygen due to its stable half-filled 2p³ configuration.