Cambridge 9701 · counted from 23 papers
Most common topics in AS Chemistry 9701
Across 23 real Cambridge 9701 papers from 2023 to 2025, the topic that carries the most questions is Group 2 metals: properties and trends — 53 questions, 5.8% of everything, appearing on 23 of the 23 papers. Next come Isomerism (5.5%) and Enthalpy change, ΔH (5%). The ten biggest topics together account for 44% of the questions.
Cambridge publishes a syllabus, not a weighting. These figures are counted from the papers themselves: every question Quanta holds is filed under the topic it tests, and its questions are added up. That makes this the closest thing to a real answer to “what comes up most”.
Updated 28 September 2026
Topics that came up on every paper
4 topics carried questions on all 23 papers counted — if you revise nothing else, these are the ones that have never been left out:
- Group 2 metals: properties and trends — 5.8% of all questions
- Isomerism — 5.5% of all questions
- Enthalpy change, ΔH — 5% of all questions
- Chemical equilibria — 3.9% of all questions
By syllabus section
The same questions, grouped into the syllabus’s own sections:
Every 9701 topic, ranked
All 50 topics, most questions first. “On papers” counts how many of the 23 papers gave the topic at least one question. Topics in blue have a free Quanta guide.
| # | Topic | Marks | Share | On papers |
|---|---|---|---|---|
| 1 | Group 2 metals: properties and trendsGroup 2 | 53 | 5.8% | 23/23 |
| 2 | IsomerismAn introduction to AS Level organic chemistry | 51 | 5.5% | 23/23 |
| 3 | Enthalpy change, ΔHChemical energetics | 46 | 5% | 23/23 |
| 4 | Redox and oxidation numbersElectrochemistry | 44 | 4.8% | 22/23 |
| 5 | Reacting masses and volumesAtoms, molecules and stoichiometry | 42 | 4.6% | 20/23 |
| 6 | AlcoholsHydroxy compounds | 37 | 4% | 18/23 |
| 7 | Chemical equilibriaEquilibria | 36 | 3.9% | 23/23 |
| 8 | Aldehydes and ketonesCarbonyl compounds | 36 | 3.9% | 21/23 |
| 9 | HalogenoalkanesHalogen compounds | 30 | 3.3% | 21/23 |
| 10 | Characteristic organic reactionsAn introduction to AS Level organic chemistry | 29 | 3.2% | 22/23 |
| 11 | Shapes of moleculesChemical bonding | 28 | 3% | 19/23 |
| 12 | Carboxylic acidsCarboxylic acids and derivatives | 27 | 2.9% | 19/23 |
| 13 | Particles in the atom and atomic radiusAtomic structure | 26 | 2.8% | 18/23 |
| 14 | Nitrogen and sulfurNitrogen and sulfur | 25 | 2.7% | 17/23 |
| 15 | Period 3: chemical propertiesThe Periodic Table: chemical periodicity | 25 | 2.7% | 17/23 |
| 16 | Gases and pV = nRTStates of matter | 23 | 2.5% | 19/23 |
| 17 | Ionisation energyAtomic structure | 23 | 2.5% | 19/23 |
| 18 | EstersCarboxylic acids and derivatives | 23 | 2.5% | 17/23 |
| 19 | AlkenesHydrocarbons | 22 | 2.4% | 16/23 |
| 20 | Bonding and structureStates of matter | 21 | 2.3% | 18/23 |
| 21 | Addition polymerisationPolymerisation | 18 | 2% | 18/23 |
| 22 | Temperature, rates and activation energyReaction kinetics | 18 | 2% | 15/23 |
| 23 | FormulasAtoms, molecules and stoichiometry | 18 | 2% | 12/23 |
| 24 | Rate of reactionReaction kinetics | 16 | 1.7% | 14/23 |
| 25 | Halogens and hydrogen halidesGroup 17 | 16 | 1.7% | 12/23 |
| 26 | Period 3: physical propertiesThe Periodic Table: chemical periodicity | 15 | 1.6% | 12/23 |
| 27 | Formulas, functional groups and namingAn introduction to AS Level organic chemistry | 15 | 1.6% | 10/23 |
| 28 | Brønsted–Lowry theory of acids and basesEquilibria | 13 | 1.4% | 11/23 |
| 29 | Mass spectrometryAnalytical techniques | 12 | 1.3% | 12/23 |
| 30 | AlkanesHydrocarbons | 12 | 1.3% | 11/23 |
| 31 | Covalent and dative bondingChemical bonding | 12 | 1.3% | 11/23 |
| 32 | Intermolecular forces and electronegativityChemical bonding | 12 | 1.3% | 11/23 |
| 33 | Homogeneous and heterogeneous catalystsReaction kinetics | 9 | 1% | 9/23 |
| 34 | Relative masses of atoms and moleculesAtoms, molecules and stoichiometry | 9 | 1% | 9/23 |
| 35 | Group 17: physical propertiesGroup 17 | 9 | 1% | 8/23 |
| 36 | Nitriles and hydroxynitrilesNitrogen compounds | 9 | 1% | 8/23 |
| 37 | Shapes of organic molecules; σ and π bondsAn introduction to AS Level organic chemistry | 9 | 1% | 7/23 |
| 38 | Electrons and atomic orbitalsAtomic structure | 8 | 0.9% | 8/23 |
| 39 | Infrared spectroscopyAnalytical techniques | 7 | 0.8% | 7/23 |
| 40 | The mole and the Avogadro constantAtoms, molecules and stoichiometry | 7 | 0.8% | 7/23 |
| 41 | Organic synthesisOrganic synthesis | 6 | 0.7% | 6/23 |
| 42 | Some reactions of the halide ionsGroup 17 | 6 | 0.7% | 6/23 |
| 43 | The reactions of chlorineGroup 17 | 5 | 0.5% | 5/23 |
| 44 | Primary aminesNitrogen compounds | 3 | 0.3% | 3/23 |
| 45 | Electronegativity and bondingChemical bonding | 2 | 0.2% | 2/23 |
| 46 | Ionic bondingChemical bonding | 2 | 0.2% | 2/23 |
| 47 | Metallic bondingChemical bonding | 2 | 0.2% | 2/23 |
| 48 | Dot-and-cross diagramsChemical bonding | 1 | 0.1% | 1/23 |
| 49 | Hess’s lawChemical energetics | 1 | 0.1% | 1/23 |
| 50 | IsotopesAtomic structure | 1 | 0.1% | 1/23 |
How this was counted
Each question is filed under the one topic it mainly tests. Where a part also draws on a second topic, it counts only once, under the first — so these numbers slightly understate topics that mostly appear as support for others, and never double-count. Figures cover the 23 9701 papers Quanta has mapped, 2023–2025; they describe what those papers asked, not what a future paper will. What each paper needed for each grade →
Practise Chemistry against real mark schemes
Quanta has real Cambridge AS Chemistry 9701 past-paper questions, with every answer explained after you commit to it and each question tied to the syllabus topic it tests — and it tracks which skills you’re missing. Free for individual students.
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What topic comes up most in 9701?
Group 2 metals: properties and trends, with 53 questions across 23 papers — 5.8% of the total — appearing on 23 of them. Isomerism and Enthalpy change, ΔH are next.
Is this the official Cambridge weighting?
No — Cambridge does not publish topic weightings. These are counted from real past papers, which makes them a measurement of what has been asked rather than an official rule. The pattern is stable year to year, which is what makes it useful for deciding where revision time goes.
Should I only revise the most common topics?
No — any syllabus topic can be examined. But the ranking tells you where marks have concentrated, and the topics near the top are the ones where being secure pays back most. The ones that appeared on every paper are the safest place to start.