State the reasons, why carbon cannot (i) Lose four electrons to form C⁴⁺ cation, and (ii) Gain four electrons to form C⁴⁻ anion. How does carbon overcome this problem to form compounds ?
Generated by claude-sonnet-4-6 · 2026-06-15 06:51 · grounding rag
Model Answer
(i) Cannot form C⁴⁺: Carbon has 6 protons in its nucleus. Removing all 4 valence electrons would require a very large amount of energy, making C⁴⁺ formation energetically unfavourable.
(ii) Cannot form C⁴⁻: Gaining 4 electrons would place them very close to the nucleus of a small atom (carbon is small). It would be difficult for 6 protons to hold 10 electrons, making C⁴⁻ highly unstable.
Solution — Covalent bonding: Carbon overcomes this problem by sharing its 4 valence electrons with other atoms, forming 4 covalent bonds. This allows carbon to complete its octet without losing or gaining electrons entirely.
Source: Chapter 4, Carbon and its Compounds
---
Explanation
- Examiners expect two separate reasons for C⁴⁺ and C⁴⁻, then a third point on covalent bonding as the solution — matching the three-part question structure.
- Key terms to use: energy, nucleus, unstable, sharing, covalent bonds, octet.
- Don't just say "it's hard" — briefly state why (energy cost for losing; nuclear charge too small to hold extra electrons).
- This answer fits a 3-mark question (≈ 1 mark per part).