GCSE Chemistry Topics: Complete List by Board
GCSE Chemistry topics span everything from atomic structure and chemical bonding to organic chemistry and the atmosphere. Chemistry is often described as the bridge between Biology and Physics: it blends mathematical calculation with written scientific explanation, and that combination is exactly what catches students off guard if they only prepare for one style of question.
This guide lists every topic for every major exam board, organised by paper, with clear markers for Triple-only content. Use it as a revision checklist: go through each topic, mark what your child is confident with, and focus revision on the gaps.
Combined vs Triple Science: What It Means for Chemistry
Around 70% of GCSE students take Combined Science (Double Science), which covers Biology, Chemistry and Physics in reduced depth and awards two GCSE grades. The remaining 25–30% take Triple Science (Separate Sciences), earning a standalone GCSE in Chemistry with more detailed content.
The core themes are identical across both routes. Combined students cover the same topics but at a shallower level, with certain sub-topics excluded. Everything marked “Triple only” below is not in Combined Science. For a full comparison of the two routes, see our Combined vs Triple Science guide.
Chemistry requires approximately 20% mathematical skills, placing it squarely between Biology (~10%) and Physics (~40%). Students need to be comfortable with calculations (relative formula mass, moles, concentration) and extended writing (6-mark explanations of chemical processes). That dual demand is what makes Chemistry uniquely challenging. For the full difficulty comparison, see our Is GCSE Science Hard? guide.
AQA Chemistry (8462): 10 Topics Across 2 Papers
AQA is the most widely used exam board in England, chosen by roughly 55% of schools. The AQA chemistry topics are split across two papers, each lasting 1 hour 45 minutes and worth 100 marks. The specification code is 8462 for Separate Chemistry and 8464 for Combined Science Trilogy. The full specification is available on the AQA Chemistry specification page.
One thing I noticed repeatedly when working with students is that AQA's Paper 1 topics tend to feel more “learnable” because they are content-heavy (atoms, bonding, acids). Paper 2 topics like rates of reaction and organic chemistry require more application, which is where unprepared students lose marks.
Paper 1: Topics 4.1–4.5 (1h 45m, 100 marks)
Paper 1 covers the foundational chemistry: atoms, bonding, calculations, acid reactions, and energy. Topics 4.3 (Quantitative Chemistry) and 4.4 (Chemical Changes) carry the most marks and are where most students find the greatest challenge.
| Sub-topic | Key Content | Notes |
|---|---|---|
| Atoms, elements, compounds | Atoms as smallest part of an element; elements on periodic table; compounds from two or more elements chemically bonded | |
| Mixtures | Not chemically bonded; separation techniques (filtration, distillation, chromatography) | |
| History of the atom | Dalton (solid sphere) → Thomson (plum pudding) → Rutherford (nuclear model) → Bohr (electron orbits) → Chadwick (neutrons) | Sequence commonly examined |
| Atomic structure | Protons (+1, mass 1), neutrons (0, mass 1), electrons (-1, negligible mass); atomic number, mass number, isotopes | |
| Electronic structure | Electrons in shells (2, 8, 8); link to position in periodic table | |
| Periodic table development | Mendeleev’s contribution; arrangement by atomic number | |
| Group 1: Alkali metals | Li, Na, K properties; reactivity increases down the group; reactions with water | |
| Group 7: Halogens | F, Cl, Br, I properties; reactivity decreases down the group; displacement reactions | |
| Group 0: Noble gases | Full outer shells; unreactive; boiling points increase down the group |
AQA Topic 4.1: Atomic Structure and the Periodic Table
| Sub-topic | Key Content | Notes |
|---|---|---|
| Ionic bonding | Metal + non-metal; transfer of electrons; giant ionic lattice (e.g. NaCl) | |
| Covalent bonding | Non-metal + non-metal; sharing electron pairs | |
| Simple molecules | Low melting/boiling points; do not conduct electricity | |
| Giant covalent structures | Diamond (hard, high mp), graphite (layers, conducts), silicon dioxide, graphene, fullerenes | Graphene and fullerenes common Qs |
| Metallic bonding | Sea of delocalised electrons; giant metallic structure | |
| Properties from structure | Melting points, conductivity, solubility linked to bonding type | |
| Polymers | Large molecules; strong intermolecular forces; solid at room temperature | |
| Nanoparticles | High surface area to volume ratio; uses in medicine, electronics, cosmetics; risks | Triple only |
AQA Topic 4.2: Bonding, Structure, and the Properties of Matter
| Sub-topic | Key Content | Notes |
|---|---|---|
| Conservation of mass | Mass of reactants = mass of products; balanced symbol equations | |
| Relative formula mass (Mr) | Sum of relative atomic masses of all atoms in the formula | |
| Moles | Amount of substance; Avogadro’s constant (6.02 × 10²³); moles = mass ÷ Mr | Higher Tier |
| Concentration | Concentration = mass ÷ volume (g/dm³); also in mol/dm³ at HT | |
| Calculating reacting masses | Using moles to find mass of products or reactants | Higher Tier |
| Limiting reactants | The reactant that is completely used up; determines amount of product | Higher Tier |
| Percentage yield | Yield = (actual ÷ theoretical) × 100; why yield is less than 100% | Triple only |
| Atom economy | Atom economy = (Mr of useful product ÷ Mr of all products) × 100 | Triple only |
AQA Topic 4.3: Quantitative Chemistry
| Sub-topic | Key Content | Notes |
|---|---|---|
| Reactivity series | K, Na, Li, Ca, Mg, Al, C, Zn, Fe, H, Cu, Ag, Au (most to least reactive) | Must memorise order |
| Extraction of metals | Above carbon = electrolysis; below carbon = reduction with carbon | |
| Oxidation and reduction | OILRIG: Oxidation Is Loss, Reduction Is Gain (of electrons); also gain/loss of oxygen | |
| Acid + metal | Acid + metal → salt + hydrogen | |
| Acid + base/alkali | Acid + base → salt + water (neutralisation) | |
| Acid + carbonate | Acid + carbonate → salt + water + CO₂ | |
| pH scale and indicators | pH 0–14; strong acids (pH 1–2), strong alkalis (pH 13–14); universal indicator | |
| Strong vs weak acids | Strong = fully ionised (HCl); weak = partially ionised (ethanoic acid) | Higher Tier |
| Electrolysis | Molten compounds and aqueous solutions; cathode (reduction), anode (oxidation) | Required practical |
AQA Topic 4.4: Chemical Changes
| Sub-topic | Key Content | Notes |
|---|---|---|
| Exothermic reactions | Transfer energy to surroundings; temperature rises (combustion, neutralisation, oxidation) | |
| Endothermic reactions | Take in energy from surroundings; temperature drops (thermal decomposition, citric acid + sodium bicarbonate) | |
| Reaction profiles | Energy level diagrams showing activation energy and overall energy change | |
| Bond energies | Energy in = bonds broken; energy out = bonds formed; overall energy change | Higher Tier |
| Chemical cells and fuel cells | Producing electricity from chemical reactions; hydrogen fuel cells | Triple only |
AQA Topic 4.5: Energy Changes
Paper 2: Topics 4.6–4.10 (1h 45m, 100 marks)
Paper 2 covers more applied chemistry: rates of reaction, organic chemistry, analysis, the atmosphere, and sustainability. These topics involve more real-world context questions, where students must apply their knowledge to unfamiliar scenarios.
| Sub-topic | Key Content | Notes |
|---|---|---|
| Factors affecting rate | Temperature, concentration, surface area, catalysts, pressure (gases) | |
| Collision theory | Particles must collide with sufficient energy (≥ activation energy); more frequent/energetic collisions = faster rate | |
| Measuring rate | Change in mass (balance), volume of gas collected, colour change/turbidity | Required practical |
| Reversible reactions | Products can reform reactants; indicated by ⇌ symbol | |
| Dynamic equilibrium | Rate of forward reaction = rate of backward reaction; closed system | Higher Tier |
| Le Chatelier’s principle | System opposes changes in temperature, pressure, or concentration | Higher Tier |
AQA Topic 4.6: The Rate and Extent of Chemical Change
| Sub-topic | Key Content | Notes |
|---|---|---|
| Crude oil | Mixture of hydrocarbons; separated by fractional distillation based on boiling point | |
| Alkanes | Saturated hydrocarbons (CₙH₂ₙ₊₂): methane, ethane, propane, butane | |
| Properties and trends | As chain length increases: viscosity increases, flammability decreases, boiling point increases | |
| Cracking | Thermal cracking (high temperature) and catalytic cracking (catalyst + moderate temperature) | |
| Alkenes | Unsaturated (C=C double bond); test with bromine water (decolourises) | Triple only |
| Alcohols | Functional group -OH; methanol, ethanol, propanol; uses as fuels and solvents | Triple only |
| Carboxylic acids | Functional group -COOH; ethanoic acid (vinegar); weak acids | Triple only |
| Esters | Formed from alcohol + carboxylic acid; fruity smells; uses in flavourings and perfumes | Triple only |
| Polymerisation | Addition polymerisation (from alkenes); condensation polymerisation (Triple only) | Triple only (condensation) |
AQA Topic 4.7: Organic Chemistry
| Sub-topic | Key Content | Notes |
|---|---|---|
| Pure substances vs mixtures | Pure = single melting/boiling point; mixtures melt/boil over a range | |
| Formulations | Mixtures designed for a specific purpose (paints, medicines, alloys) | |
| Chromatography | Separating mixtures; Rf value = distance moved by substance ÷ distance moved by solvent | Required practical |
| Gas tests | H₂ (squeaky pop), O₂ (relights splint), CO₂ (limewater turns milky), Cl₂ (bleaches litmus) | Commonly examined |
| Flame tests | Li (red), Na (yellow), K (lilac), Ca (orange-red), Cu (green) | Triple only |
| Identifying ions | Precipitates with NaOH: Cu²⁺ (blue), Fe²⁺ (green), Fe³⁺ (brown); carbonates, halides, sulfates | Triple only |
AQA Topic 4.8: Chemical Analysis
| Sub-topic | Key Content | Notes |
|---|---|---|
| Early atmosphere | Volcanic activity produced mainly CO₂ and water vapour | |
| How oxygen levels increased | Photosynthesis by early plants and algae over billions of years | |
| Today’s atmosphere | ~78% nitrogen, ~21% oxygen, ~0.04% CO₂, ~1% argon | Percentages commonly tested |
| Greenhouse gases | CO₂, methane, water vapour; trap infrared radiation | |
| Climate change | Caused by increased greenhouse gas emissions; carbon footprint | |
| Atmospheric pollutants | CO (incomplete combustion), SO₂ (acid rain), NOₓ (from engines), particulates (health) |
AQA Topic 4.9: Chemistry of the Atmosphere
| Sub-topic | Key Content | Notes |
|---|---|---|
| Sustainable development | Meeting current needs without compromising future generations | |
| Potable water | Sedimentation → filtration → chlorination; desalination for seawater | Required practical |
| Waste water treatment | Screening, sedimentation, biological treatment, further chemical treatment | |
| Life cycle assessment (LCA) | Assessing environmental impact from raw materials to disposal | |
| Reduce, reuse, recycle | Reducing use of limited resources; recycling metals and polymers | |
| Corrosion and alloys | Rusting of iron (needs water + oxygen); alloys as harder mixtures of metals | Triple only |
| Ceramics and composites | Properties and uses of ceramics, polymers, and composite materials | Triple only |
| Haber process | N₂ + 3H₂ ⇌ 2NH₃; 450°C, 200 atm, iron catalyst; compromise conditions | Triple only |
AQA Topic 4.10: Using Resources
Edexcel Chemistry (1CH0): 9 Topics Across 2 Papers
Edexcel organises its Edexcel chemistry GCSE topics differently from AQA. There are 9 topics, and one critical quirk to be aware of: Topic 1 (Key Concepts in Chemistry) is examined on both papers. This means the core foundations (atomic structure, bonding, calculations) are always fair game, regardless of which paper your child is sitting.
Topic 1 (Key Concepts in Chemistry) is examined on both Paper 1 and Paper 2. This is unique to Edexcel. Students must revise atomic structure, bonding, formulae, and calculations for every exam sitting, not just Paper 1. It covers the foundational chemistry that underpins all other topics.
Paper 1: Topics 1–5 (1h 45m, 100 marks)
| Topic | Key Content | Notes |
|---|---|---|
| 1: Key Concepts in Chemistry | Atomic structure, periodic table, ionic/covalent/metallic bonding, formulae, equations, moles (HT), energetics calculations | Tested on BOTH papers |
| 2: States of Matter and Mixtures | Particle model, changes of state, separation techniques, chromatography, purity | |
| 3: Chemical Changes | Acids, bases, salts, neutralisation, reactivity series, metal extraction, electrolysis, pH scale | |
| 4: Extracting Metals and Equilibria | Extraction methods, life cycle assessment, recycling, dynamic equilibrium (HT), Haber process | |
| 5: Separate Chemistry 1 | Transition metals, nanoparticles, titrations, mole calculations | Triple only |
Edexcel Topics 1–5 (Paper 1)
Paper 2: Topics 1, 6–9 (1h 45m, 100 marks)
| Topic | Key Content | Notes |
|---|---|---|
| 1: Key Concepts in Chemistry | Same as above; atomic structure, bonding, formulae, equations | Also on Paper 1 |
| 6: Groups in the Periodic Table | Group 1 (alkali metals), Group 7 (halogens), Group 0 (noble gases); properties and trends | |
| 7: Rates of Reaction and Energy Changes | Rate factors, collision theory, catalysts, exothermic/endothermic reactions, bond energies (HT) | |
| 8: Fuels and Earth Science | Hydrocarbons, fractional distillation, combustion, cracking, alkenes, polymers, atmosphere, climate change, carbon footprint | |
| 9: Separate Chemistry 2 | Alcohols, carboxylic acids, esters, quantitative analysis, water treatment | Triple only |
Edexcel Topics 6–9 (Paper 2)
Edexcel requires 8 core practicals for Separate Chemistry and 7 for Combined Science. These cover making salts, electrolysis, temperature changes, rates of reaction, chromatography, water purification, titrations (Triple only), and identifying ions (Triple only).
OCR Gateway Chemistry (J248): 6 Topics Across 2 Papers
OCR chemistry topics are organised into just 6 topics plus a practical skills component (C7) that is assessed across both papers. The specification code is J248 for Separate Chemistry and J250 for Combined Science A. OCR has the lowest total marks at 180 (compared to 200 for AQA and Edexcel).
Paper 1: C1–C3 (1h 45m, 90 marks)
| Topic | Key Content | Notes |
|---|---|---|
| C1: Particles | Particle model, states of matter, atomic structure, isotopes, electronic configuration, history of atomic model | Combines particle theory with atomic structure |
| C2: Elements, Compounds and Mixtures | Periodic table, Group 1/7/0, bonding (ionic, covalent, metallic), properties from structure, separation techniques, purity | |
| C3: Chemical Reactions | Balanced equations, acid reactions, neutralisation, redox (OILRIG), electrolysis, energetics (exo/endothermic), bond energies (HT) | Covers acids and energy in one topic |
OCR Gateway Topics C1–C3 (Paper 1)
Paper 2: C4–C6 (1h 45m, 90 marks)
| Topic | Key Content | Notes |
|---|---|---|
| C4: Predicting and Identifying Reactions | Reactivity series, displacement reactions, identifying ions (flame tests, precipitates), gas tests | |
| C5: Monitoring and Controlling Reactions | Moles (HT), concentration, rate of reaction, collision theory, catalysts, dynamic equilibrium (HT), Le Chatelier’s principle (HT) | |
| C6: Global Challenges | Haber process, metal extraction, organic chemistry (crude oil, alkanes, alkenes, polymers), atmosphere, climate change, water treatment, sustainability, LCA | Broadest topic; covers organic + environmental |
OCR Gateway Topics C4–C6 (Paper 2)
OCR combines topics that AQA separates. For example, OCR's C3 covers both acid reactions and energetics, while AQA has these as separate topics (4.4 and 4.5). The same amount of content is tested; it is simply grouped differently.
OCR's C7 is not a content topic but a practical skills assessment that runs across both papers. Questions about experimental design, variables, data analysis, and accuracy appear throughout. At least 15% of marks are practical-based. Edexcel and AQA assess practical skills in the same way; they just do not give it a separate topic code.
No Equation Sheet for Chemistry
This catches parents and students off guard every year. Physics has been provided with an equation sheet (currently available from 2025 to 2027), but Chemistry has no formula or equation sheet at all. Students must memorise every key formula.
A periodic table is provided in every Chemistry exam, for every exam board. However, there is no formula/equation sheet. Students must memorise formulae for relative formula mass, moles, concentration, and (for Triple) percentage yield and atom economy. This is a common source of confusion because Physics does have an equation sheet (2025–2027), but that policy does not extend to Chemistry.
Required Practicals (AQA)
At least 15% of Chemistry exam marks test practical knowledge. There is no separate practical exam, but questions about method, variables, accuracy, and results interpretation appear throughout both papers. Here are AQA's 8 required practicals for Separate Chemistry:
For a full breakdown of required practicals across all three sciences, see our GCSE Science Required Practicals guide.
2025 Results in Context
Chemistry had the highest pass rate and highest top-grade rate of all three sciences in 2025. That does not mean it is the easiest; it reflects the self-selected cohort of students who choose to sit Separate Chemistry.
| Measure | Separate Chemistry | Combined Science |
|---|---|---|
| Grade 4+ pass rate | 91.5% | 57.6% |
| Grades 7–9 | 46.1% | 9.1% |
| Approximate entries | ~183,000 | ~470,000 |
| Year-on-year trend | Down ~6% from 2024 | Up ~1–2% |
GCSE Chemistry Results: 2025 (Source: Tes / FFT Education Datalab)
Chemistry's 91.5% grade 4+ rate is slightly above Biology (89.4%) and Physics (90.8%). The difference is small, and it mainly reflects which students choose Triple Science. Schools typically enter their strongest science students for Separate Sciences, so the cohort is inherently higher-performing. If your child is on Combined Science, compare their progress against the 57.6% Combined pass rate, not the Triple figure.
This context helps put your child's results into perspective. The wider trend in science entries is also worth understanding, particularly if your child is deciding between Combined and Triple.
Triple Science entries fell approximately 6% in 2025 across all three sciences. This is driven by timetabling and staffing pressures in schools, not by exam difficulty. Combined Science entries increased by around 1–2%. Ofqual described 2025 as a year of “stability” in grading standards. Source: FFT Education Datalab.
How to Use This GCSE Chemistry Topics List for Revision
Having every topic laid out is only useful if your child actually works through it systematically. From what I've seen working with students preparing for science GCSEs, the biggest gap is usually not knowledge of the content but knowledge of what is and is not on their specific exam. Students who spend even one hour going through the specification with a highlighter start their revision with a significant advantage.
Confirm the exam board and tier
Check with school: AQA (8462), Edexcel (1CH0), or OCR (J248). Also confirm whether your child is on Combined or Triple, and whether they are Foundation or Higher Tier.
Traffic-light each topic
Go through the topic list above and mark each sub-topic green (confident), amber (needs revision), or red (not yet understood). Be honest, not optimistic.
Focus on red and amber topics first
Do not waste revision time re-reading topics your child already knows. This is the single most common revision mistake: students revise comfortable topics because it feels productive.
Skip Triple-only content if on Combined
Combined Science students should ignore everything marked "Triple only". Revising content that will not be examined is time taken away from what will be.
Practise calculations early and often
Chemistry calculations (moles, concentration, Mr) are where students lose marks most often. These need repeated practice, not just reading. Work through past paper calculation questions regularly.
Use past papers for the final stretch
Once core revision is done, switch to full past papers under timed conditions. Mark them using the official mark scheme, not your own judgement of what is "close enough".
Common Mistakes to Avoid
- •Revising topics you already know (feels good, achieves little)
- •Not memorising formulae (no equation sheet is provided)
- •Ignoring practical questions (worth 15%+ of marks)
- •Not knowing which exam board you are studying
What High Performers Do
- •Traffic-light topics and target weak areas
- •Practise calculations weekly from Year 10
- •Study the mark scheme alongside past papers
- •Know every required practical method and variables
For detailed revision strategies, see our Revision Techniques That Actually Work guide. For a free printable timetable template, see our GCSE Revision Timetable guide. And for a full comparison of what Combined and Triple Science actually involves, see our Combined vs Triple Science guide.
