When one parent asks another, “My child enjoys Chemistry, but how do I know what the course actually covers? I keep finding different topic lists online,” it’s an understandable concern. The IB Chemistry syllabus was revised for first assessment in May 2025, so some older notes and resources follow a different structure.
Sev7n offers one-to-one online IB Chemistry tuition for SL and HL students, with support from active IB Examiners, including help with syllabus concepts, exam practice and the scientific investigation.
The current course is organised around two connected themes: Structure and Reactivity. This guide explains the six strands and all 22 topics, the differences between SL and HL, the assessment structure and practical ways to plan your revision. The current guide was first assessed in May 2025.
Quick answer: What is the IB Chemistry syllabus?
The IB Chemistry syllabus covers Structure and Reactivity, divided into six strands and 22 topics. SL students have 110 recommended syllabus-content hours, while HL students have 180. Including the experimental programme, the recommended totals are 150 hours at SL and 240 at HL.
The final grade is based on Paper 1, Paper 2 and the scientific investigation:
Paper 1: 36%
Paper 2: 44%
Scientific investigation (IA): 20%
What changed in the current IB Chemistry syllabus?
The course now groups chemistry content into the themes of Structure and Reactivity. It has no separate optional topic or Paper 3. Paper 1 is divided into Paper 1A and Paper 1B, and the former Group 4 project has been replaced by the collaborative sciences project.
Area | Current course |
|---|---|
Organisation | Two themes: Structure and Reactivity |
Course content | Six strands and 22 topics |
Options | No separate optional topics |
Examination papers | Paper 1A, Paper 1B and Paper 2 |
Practical programme | Includes practical work, the collaborative sciences project and the scientific investigation |
If you’re using an older textbook or past paper, check that its topics and exam format match the course first assessed in 2025.
IB Chemistry syllabus at a glance
The six strands are divided between the two course themes. HL students study the same strands as SL students, with additional content and greater depth in several areas.
Theme | Strand | SL content hours | HL content hours |
|---|---|---|---|
Structure | S1. Models of the particulate nature of matter | 17 | 21 |
Structure | S2. Models of bonding and structure | 20 | 30 |
Structure | S3. Classification of matter | 16 | 31 |
Reactivity | R1. What drives chemical reactions? | 12 | 22 |
Reactivity | R2. How much, how fast and how far? | 21 | 31 |
Reactivity | R3. What are the mechanisms of chemical change? | 24 | 45 |
Syllabus-content total | 110 | 180 | |
Experimental programme | 40 | 60 | |
Recommended total teaching hours | 150 | 240 |
These are recommended teaching hours, not a revision timetable. Your school may teach the strands in a different order.
Complete IB Chemistry topic-by-topic breakdown
The explanations below summarise what students study in each topic. The exact depth and learning outcomes should be checked against the current Chemistry guide and your school’s course plan.
Structure 1: Models of the particulate nature of matter
SL: 17 hours · HL: 21 hours
This strand introduces the particles that make up matter and the calculations chemists use to measure them.
S1.1 — Introduction to the particulate nature of matter: Elements, compounds, mixtures, states of matter and separation methods.
S1.2 — The nuclear atom: Protons, neutrons, electrons, isotopes and mass spectra.
S1.3 — Electron configurations: Energy levels, orbitals and how electron arrangements relate to the periodic table.
S1.4 — Counting particles by mass: the mole: Molar mass, the mole, empirical formulas and concentration.
S1.5 — Ideal gases: Relationships between gas pressure, volume, temperature and amount of substance.
Study tip: Make sure you can move confidently between mass, moles and number of particles. These calculations appear throughout the course.
Structure 2: Models of bonding and structure
SL: 20 hours · HL: 30 hours
This strand explores how the arrangement and bonding of particles affect a substance’s properties.
S2.1 — The ionic model: Ionic bonding, lattices and the properties of ionic compounds.
S2.2 — The covalent model: Lewis structures, molecular shapes, polarity and intermolecular forces.
S2.3 — The metallic model: Metallic bonding and properties such as conductivity and malleability.
S2.4 — From models to materials: Applying bonding models to materials such as alloys and polymers.
Study tip: Practise drawing structures and explaining how they relate to properties. Don’t stop at naming a bond type; connect the structure to the behaviour of the substance.
Structure 3: Classification of matter
SL: 16 hours · HL: 31 hours
Students use patterns in the periodic table and organic chemistry to classify substances and understand their behaviour.
S3.1 — The periodic table: classification of elements: Periodic trends, element properties and the behaviour of elements and their compounds.
S3.2 — Functional groups: classification of organic compounds: Organic structures, functional groups, naming and ways of identifying organic substances.
Study tip: Practise recognising functional groups in different structural representations. It makes later organic chemistry easier to follow.
Reactivity 1: What drives chemical reactions?
SL: 12 hours · HL: 22 hours
This strand looks at energy changes and the factors that help explain whether a reaction is energetically favourable.
R1.1 — Measuring enthalpy changes: Exothermic and endothermic reactions, calorimetry and enthalpy calculations.
R1.2 — Energy cycles in reactions: Hess’s law and using energy cycles to calculate enthalpy changes.
R1.3 — Energy from fuels: Combustion and the energy released by fuels.
R1.4 — Entropy and spontaneity: An HL topic covering entropy and Gibbs energy.
For calorimetry calculations, the relationship is:
q = mcΔT
where q is heat energy, m is mass, c is specific heat capacity and ΔT is the temperature change. Check units and signs carefully.
Study tip: When using energy cycles, show how the equations combine. When doing calorimetry, write the units beside your values before calculating.
Reactivity 2: How much, how fast and how far?
SL: 21 hours · HL: 31 hours
This strand focuses on the amount of chemical change, reaction rates and equilibrium.
R2.1 — How much? The amount of chemical change: Balanced equations, stoichiometry, limiting reactants and yield.
R2.2 — How fast? The rate of chemical change: Collision theory and factors that affect reaction rates.
R2.3 — How far? The extent of chemical change: Reversible reactions, equilibrium and how conditions affect the position of equilibrium.
Study tip: For equilibrium questions, explain why the system changes. Saying only that equilibrium “shifts left” or “shifts right” may not fully answer the question.
Reactivity 3: What are the mechanisms of chemical change?
SL: 24 hours · HL: 45 hours
This strand explains how chemical changes happen through the transfer or sharing of protons, electrons and electron pairs.
R3.1 — Proton transfer reactions: Acids and bases, pH and acid–base reactions.
R3.2 — Electron transfer reactions: Redox reactions, oxidation states and electrochemical processes.
R3.3 — Electron sharing reactions: Reactions involving the sharing of electrons, including radical reactions.
R3.4 — Electron-pair sharing reactions: Organic reactions and mechanisms involving electron pairs.
Study tip: When drawing a reaction mechanism, check what each arrow represents and where it starts and ends. A clear drawing helps show the chemical reasoning behind each step.
IB Chemistry SL vs HL: Which should you choose?
SL and HL share the same overall course structure, but HL requires more teaching hours and greater depth in several topics.
Feature | SL | HL |
|---|---|---|
Recommended total teaching hours | 150 | 240 |
Syllabus-content hours | 110 | 180 |
Experimental-programme hours | 40 | 60 |
Exam papers | Paper 1 and Paper 2 | Paper 1 and Paper 2 |
Scientific investigation | 20% of the grade | 20% of the grade |
Course depth | Core content | Core content plus additional HL depth and content |
HL may suit students who enjoy Chemistry and are prepared for more advanced content and demanding calculations. If you’re considering medicine, chemical engineering, pharmacy or a related degree, check the entry requirements for the specific universities and courses you may apply to. Requirements vary.
SL may be a suitable choice if you need Chemistry as part of the Diploma but don’t plan to pursue a Chemistry-related degree. Discuss the choice with your school’s Diploma coordinator.
How is IB Chemistry assessed?
Paper 1 and Paper 2 together make up 80% of the final grade. The scientific investigation makes up the remaining 20%. The paper timings differ between SL and HL.
Component | SL duration | HL duration | Weighting |
|---|---|---|---|
Paper 1A and Paper 1B | 1 hour 30 minutes | 2 hours | 36% |
Paper 2 | 1 hour 30 minutes | 2 hours 30 minutes | 44% |
Scientific investigation (IA) | 10 recommended hours | 10 recommended hours | 20% |
Paper 1: Multiple-choice and data-based questions
Paper 1 has two parts:
Paper 1A includes multiple-choice questions.
Paper 1B includes data-based questions and questions about experimental work.
Practise reading graphs and tables, interpreting results and applying Chemistry ideas to unfamiliar information—not only recalling definitions.
Paper 2: Short-answer and extended-response questions
Paper 2 tests your understanding through calculations, short answers and extended responses. Read the command term carefully. For example, an explain question asks for reasons, while a describe question asks you to state relevant features or patterns.
Show your working in calculations, use appropriate units and link each explanation to the question.
The IB Chemistry scientific investigation (IA)
The scientific investigation is an individual investigation that contributes 20% of your final Chemistry grade. Students develop a research question, collect and analyse data, draw a conclusion and evaluate their work. The report has a maximum word count of 3,000 words; ask your teacher what is included in the count and follow your school’s instructions.
The investigation is assessed across four criteria:
Criterion | What it assesses |
|---|---|
Research design | How well the investigation is planned to answer the research question |
Data analysis | How effectively the data is processed and interpreted |
Conclusion | How well the conclusion answers the research question using the results |
Evaluation | How well the investigation’s limitations and possible improvements are considered |
Choosing a research question
A useful research question should be focused, measurable and possible to investigate safely with the equipment available at your school. For example:
How does temperature affect the rate of reaction between sodium thiosulfate and hydrochloric acid?
Before settling on a question, consider whether you can define the variables clearly, collect enough reliable data and explain the results using Chemistry concepts. Your teacher must approve your plan and practical work.
Your investigation must be your own. A tutor or teacher may guide your understanding and provide feedback, but the research, analysis and submitted work should reflect your own decisions and learning.
A practical IB Chemistry revision plan
Schools choose their own teaching order, so treat this as an example for organising revision—not a required sequence.
Revision period | Suggested focus |
|---|---|
Week 1 | Structure 1 and 2: particles, atomic structure, mole calculations and bonding |
Week 2 | Structure 3 and Reactivity 1: periodic trends, organic structures and energetics |
Week 3 | Reactivity 2 and 3: stoichiometry, rates, equilibrium, acids and bases, redox and mechanisms |
Week 4 | Review weaker topics, practise timed papers and check HL content if applicable |
During revision, keep a list of questions you get wrong. Mark whether each mistake came from a concept you didn’t understand, a calculation error, a missed unit or misreading the question. Use that list to plan what to practise next.
For full mock exams, use papers and sample materials that match the current course. Older papers may still help you practise concepts that remain in the syllabus, but their structure may differ.
IB Chemistry syllabus FAQs
When did the IB Chemistry syllabus change?
The current course was first assessed in May 2025. Students taking the 2026–27 course should use materials for the revised syllabus.
How many topics are in the IB Chemistry syllabus?
The course has 22 topics grouped into six strands: Structure 1–3 and Reactivity 1–3. SL and HL follow the same overall structure, with additional depth and content at HL.
Is there a Paper 3 in IB Chemistry?
No. The current assessment structure includes Paper 1, which has parts 1A and 1B, Paper 2 and the scientific investigation.
How many teaching hours are recommended for IB Chemistry?
The recommended total is 150 hours for SL and 240 hours for HL. This includes syllabus-content hours and the experimental programme.
Is the scientific investigation the same at SL and HL?
Both levels complete a scientific investigation that contributes 20% of the final Chemistry grade. Follow your school’s guidance on the requirements and assessment criteria.
Can I use old IB Chemistry past papers to revise?
You can use older questions for Chemistry concepts that are still part of the current course. For full exam practice, use sample papers and questions that match the assessment structure first assessed in 2025.
Get support with IB Chemistry
If you’re stuck on a particular strand, start by identifying the gap. It might be mole calculations, reaction mechanisms, experimental data or writing explanations for Paper 2. Focused practice on that skill can be more useful than rereading the entire syllabus.
Sev7n provides online IB Chemistry tuition for SL and HL students, with one-to-one lessons, mock-paper practice and IA guidance. The aim is to help you understand the Chemistry and build the skills to apply it independently.