If carbon were to form a C⁴⁺ ion by losing all four of its valence electrons, which shell would become its ou…

Question

If carbon were to form a C⁴⁺ ion by losing all four of its valence electrons, which shell would become its outermost shell, and how many electrons would it contain? Explain why such an arrangement makes ionic bonding energetically unfavourable for carbon compared to covalent bonding.

Accepted Answer

## Model Answer If carbon loses all four valence electrons to form C⁴⁺, the **K shell** (first shell) would become its outermost shell, containing **2 electrons**. This arrangement is energetically unfavourable because removing four electrons from carbon requires a **very large amount of energy**. The resulting C⁴⁺ cation would have six protons holding only two electrons, making it highly unstable. Therefore, carbon prefers **sharing** its four valence electrons to form stable covalent bonds instead. *Source: Chapter 4, Section 4.1 — Bonding in Carbon: The Covalent Bond* --- ## Explanation - Examiners expect you to correctly identify the K shell with 2 electrons (carbon's configuration is 2, 4). - The key reasoning from the textbook: forming C⁴⁺ needs a **large amount of energy** — state this explicitly. - Mention the instability (6 protons holding 2 electrons) to earn full marks. - Don't write more than this — 2 marks = roughly 2 key points.

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