Answer the question on the basis of passage given below:
Second period elements of p-Block differ from the rest of their group members due to their small atomic size, high electronegativity, high ionization enthalpy and absence of d-orbitals.
The elements from the second period like C, N, O have unique property of forming pπ–pπ multiple bonds whereas other heavier elements of p-block form dπ–pπ multiple bonds. This changes the properties of second period elements to great extent. Also the single bond strength of the p-block elements with their own atoms gets affected by their atomic size and presence of lone pairs.
Inert pair effect also affects the properties of the p-Block elements especially for those elements which are present from 4th period onward and this happens due to poor screening effect of inner (n–1)d subshell electrons.
Catenation tendency of Nitrogen is weaker than Phosphorus, because
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \(N-N\) bond strength is weaker than \(P-P\) bond strength
Catenation is the linking of atoms of the same element by single bonds, so it depends on the strength of the single bond. The N–N single bond is weaker than the P–P single bond, so nitrogen shows a weaker catenation tendency than phosphorus.
Why the other options are incorrect
Option (1) Nitrogen is smaller in atomic size than phosphorus — Incorrect. The small size is the cause of the lone-pair repulsion, but the property that decides catenation is the weak N–N single bond.
Option (2) Nitrogen forms multiple bonds whereas phosphorus does not — Incorrect. The ability to form multiple bonds does not explain chains of singly bonded atoms.
Option (4) N–N bond strength is stronger than P–P bond strength — Incorrect. This is the reverse of the fact; a stronger N–N bond would make catenation easier in nitrogen.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Anomalous Properties of Nitrogen
