Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Both rhombic and monoclinic sulphur exist as S₈ while oxygen exists as O₂.
Reason (R) : Oxygen forms p π-p π multiple bonds with itself and other elements having small size and high electronegativity like C, N, which is not possible for sulphur.
In the light of the above statements, choose the most appropriate answer from the options given below :

Solution

Chemistry ma’am · 4 steps

Oxygen double bonds with itself, so O₂ is enough; sulphur cannot, so it rings up as S₈.

1. Check the assertion. Rhombic and monoclinic sulphur are both made of puckered S₈ crown rings, packed differently in the crystal. Oxygen is a diatomic gas, O₂. So (A) is correct.
2. Why oxygen stays diatomic. Oxygen is small and highly electronegative, so its 2p orbitals overlap well side-on and give strong pπ–pπ bonds. The double bond O=O satisfies each atom in a two-atom molecule. The same small size lets oxygen form pπ–pπ bonds with C and N, as in C=O and N=O.
3. Why sulphur catenates. Sulphur's 3p orbitals are larger and more diffuse, so their side-on overlap is poor and pπ–pπ bonds are weak. Each sulphur instead forms single σ bonds to two neighbours. These S-S links close into an S₈ ring.
4. So. (R) is correct, and it is exactly the reason oxygen is O₂ while sulphur is S₈. The answer is (d).

The idea to keep. Only the small second-period atoms (C, N, O) form strong pπ–pπ bonds. Their heavier group-mates switch to single-bonded chains and rings, like S₈ and P₄.

Answer from the NTA final answer key. Solution by PrepWiser.