Science (086) — AI-generated practice question

No, the student is not correct.

Oxygen needs two more electrons to complete its octet, but this does not mean it must form double bonds. In a water molecule (H₂O), oxygen shares one electron with each of the two hydrogen atoms, forming two single covalent bonds. Each hydrogen needs only one electron to complete its duplet. This satisfies oxygen's octet (2 + 2 shared + 4 non-bonding = 8 electrons) without any double bond.

Double bonds form only when a single bond leaves valencies unsatisfied, as in ethene (C₂H₄).

Source: Chapter 4, Section 4.2 / 4.2.1

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• Examiners expect you to clearly state the student is wrong, then explain why using electron sharing logic.
• Key point: needing 2 more electrons means forming 2 bonds, not necessarily 1 double bond. H₂O forms two separate single bonds with two H atoms.
• Mentioning octet/duplet satisfaction shows conceptual clarity — that earns full marks.
• Contrast with a genuine double-bond situation (like ethene) to strengthen your answer — useful for the third mark.