Cambridge IGCSE Chemistry (0620) for examination in 2026 is organised into 12 topic areas and assessed through three papers. You can be entered for Core (Core content only) or Extended (Core plus Supplement). If you’re chasing an A*, you’ll be entered for Extended: Paper 2 Multiple Choice (45 minutes, 40 marks, 30%), Paper 4 Theory (1 hour 15 minutes, 80 marks, 50%), plus either Paper 5 Practical Test or Paper 6 Alternative to Practical (40 marks, 20%). 

How marks are awarded

Assessment objectives are split across knowledge, problem-solving, and practical skills:
• AO1 Knowledge with understanding: 50%
• AO2 Handling information and problem-solving: 30%
• AO3 Experimental skills and investigations: 20%
Keep that balance in mind when you plan revision: facts and definitions, calculations and unfamiliar contexts, plus experimental technique.

1) States of matter

1.1 Solids, liquids and gases: particle arrangement, motion, and changes of state.
1.2 Diffusion: diffusion in gases and solutions; Supplement links it to kinetic particle theory and heating/cooling curves. 

2) Atoms, elements and compounds

2.1 Elements, compounds and mixtures.
2.2 Atomic structure and the Periodic Table: protons, neutrons, electrons, electron arrangement (proton number 1–20), and group/period links.
2.3 Isotopes.
2.4 Ions and ionic bonds: dot-and-cross diagrams and properties of ionic compounds.
2.5 Simple molecules and covalent bonds.
2.6 Giant covalent structures (graphite, diamond, SiO2).
2.7 Metallic bonding and metal properties.

3) Stoichiometry

3.1 Formulae: word and symbol equations with state symbols; Supplement adds empirical formula and ionic equations.
3.2 Relative masses (Ar, Mr) and simple reacting masses.
3.3 The mole: Avogadro constant (6.02 × 10^23), molar gas volume at r.t.p. (24 dm^3), concentration (g/dm^3 and mol/dm^3), titration calculations, yields, purity, and composition.

4) Electrochemistry

4.1 Electrolysis: identifying anode/cathode/electrolyte, predicting products in molten and aqueous cases, and electroplating; Supplement adds half-equations and charge transfer detail.
4.2 Hydrogen–oxygen fuel cells, including benefits and drawbacks in Supplement. 

5) Chemical energetics

5.1 Exothermic and endothermic reactions: reaction pathway diagrams, activation energy, bond energy ideas, and energy calculations. 

6) Chemical reactions

6.1 Physical and chemical changes.
6.2 Rate of reaction: methods, graphs, and collision theory in Supplement.
6.3 Reversible reactions and equilibrium: conditions for equilibrium and how changes affect position; industrial conditions for the Haber and Contact processes sit in Supplement.
6.4 Redox: oxidation/reduction definitions, oxidation numbers, oxidising and reducing agents, and key qualitative redox tests. 

7) Acids, bases and salts

7.1 Properties, indicators, pH, neutralisation, and strong vs weak acids (Supplement).
7.2 Oxides: acidic, basic, and amphoteric (Supplement).
7.3 Preparation of salts: titration and excess solid methods, plus solubility rules.

8) The Periodic Table

8.1 Arrangement and trends across a period; prediction from position.
8.2 Group I trends.
8.3 Group VII trends and displacement.
8.4 Transition elements: coloured compounds and catalysis; variable oxidation states in Supplement.
8.5 Noble gases and electronic configuration. 

9) Metals

9.1 Physical and chemical properties, including reactions with acids, water/steam, and oxygen.
9.2 Uses of aluminium and copper linked to properties.
9.3 Alloys: brass and stainless steel; Supplement links structure to hardness.
9.4 Reactivity series and displacement.
9.5 Corrosion and rust prevention (Supplement).
9.6 Extraction: iron in the blast furnace and aluminium by electrolysis (Supplement). 

10) Chemistry of the environment

10.1 Water: chemical tests for water, water treatment, and key ideas linked to potable water.
10.2 Fertilisers: ammonium salts, nitrates, and NPK fertilisers for plant growth.
10.3 Air quality and climate: composition of clean, dry air, sources of pollutants, environmental impacts, and strategies to reduce effects. 

11) Organic chemistry

11.1 Formulae, functional groups, homologous series, saturation, and structural isomerism (Supplement).
11.2 Naming organic compounds: core set plus longer unbranched chains in Supplement.
11.3 Fuels and petroleum: fractional distillation, trends in fraction properties, and uses.
11.4 Alkanes: combustion and chlorination (Supplement).
11.5 Alkenes: cracking, bromine test, and addition reactions (Supplement).
11.6 Alcohols: ethanol by fermentation and hydration of ethene; comparison points in Supplement.
11.7 Carboxylic acids and esters (reactions and naming).
11.8 Polymers: poly(ethene), plastics and environmental challenges, plus condensation polymers, PET, and proteins in Supplement.

12) Experimental techniques and chemical analysis

12.1 Experimental design, apparatus choice, and core lab vocabulary.
12.2 Acid–base titrations.
12.3 Chromatography and Rf (Supplement).
12.4 Separation and purification.
12.5 Tests for ions and gases, flame tests, and qualitative analysis notes used in practical papers. 

How to turn this into an A* plan

Make a checklist from the numbered sub-sections, then revise in loops. Start with definitions and key facts, move into calculation drills and data questions, and keep one page of practical reminders (titration steps, chromatography interpretation, ion and gas tests). Past-paper practice should be rotated across Paper 2 speed, Paper 4 structure, and practical-style questions, so accuracy and exam technique grow together each week.