Science (086) — AI-generated practice question

Carbon (atomic number 6) has 4 valence electrons and needs 4 more to achieve noble gas configuration. Forming ionic bonds is not feasible for carbon because:

1. Gaining 4 electrons would form C⁴⁻, but the nucleus with only 6 protons cannot hold 10 electrons stably.
2. Losing 4 electrons would form C⁴⁺, but this requires an extremely large amount of energy to remove four electrons, leaving just 2 electrons with 6 protons.

Therefore, carbon overcomes this problem by sharing its 4 valence electrons with other atoms, forming covalent bonds. This allows both atoms to achieve noble gas configuration without gaining or losing electrons.

Source: Chapter 4, Section 4.1 – Bonding in Carbon: The Covalent Bond

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Examiners look for two specific reasons (one for each ionic option) clearly stated — this is where most marks lie. Simply saying "carbon shares electrons" without explaining why ionic bonding is impossible will lose marks. Always use the terms C⁴⁻ and C⁴⁺ with their reasoning. The conclusion about covalent bond formation ties it together for the third mark.