Exam Focus

🎯 Exam Focus

Frequently Examined

Covalent bonding questions appear on every paper. Key patterns:

• Draw a dot-cross diagram for H₂, H₂O, NH₃, CH₄, HCl, Cl₂, O₂, N₂, CO₂ — 2-3 marks
• Explain why a substance is covalent (non-metals, electrons shared) — 2 marks
• State the number of bonds an atom makes (from electron configuration) — 1 mark
• Compare single/double/triple bonds in terms of strength and length — 2 marks
• Higher tier: Explain why N₂ is unreactive (triple bond, high bond energy) — 2 marks

Common exam trap: distinguishing between properties of simple molecular covalent substances vs giant covalent structures.

Edexcel 1CH0: Examined in Paper 1 (1CH0/1). Edexcel questions frequently ask students to draw dot-and-cross diagrams for covalent compounds (H₂O, NH₃, CH₄, CO₂) and explain why substances are covalent (non-metals, shared electrons). Questions may also ask you to compare single, double, and triple bond strength and length. In Edexcel-style questions, the command word "Suggest" appears frequently — use your chemistry knowledge to apply to an unfamiliar context.