Science (086) — AI-generated practice question

Carbon forms far more stable compounds than silicon due to two main reasons:

(i) Catenation: Carbon has a unique ability to form strong bonds with other carbon atoms, producing long chains, branched chains, and rings. The carbon–carbon bond is very strong and stable, allowing millions of compounds. Silicon also shows catenation, but silicon–silicon bonds are much weaker, so silicon chains are limited to only seven or eight atoms and are highly reactive.

(ii) Small atomic size: Carbon's nucleus is small, so it holds the shared pairs of electrons very strongly, forming exceptionally stable covalent bonds. Silicon has a larger atom, so its nucleus cannot hold shared electrons as firmly, making its bonds weaker and its compounds less stable.

Source: Chapter 4, Section 4.2 – Versatile Nature of Carbon

---

• Examiners expect two distinct, labelled points — catenation and atomic size — directly from the textbook.
• For catenation, you must contrast carbon (stable, unlimited chains) with silicon (reactive, max ~7–8 atoms).
• For atomic size, the key phrase is: small nucleus → stronger hold on shared electrons → stronger, more stable bonds.
• Avoid vague statements like "carbon is special"; use precise textbook language.