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Topics
IB Group 4 — Sciences
IB Chemistry 2026
IB Chemistry (2023 syllabus, first exams May 2025) is structured around two organising principles: Structure (models of matter) and Reactivity (how and why reactions happen). The core thesis is that structure determines reactivity. HL adds approximately 70 extra teaching hours and depth in AHL understandings throughout, plus the HL-only topic Entropy and Spontaneity (R1.4). The old Paper 3 options (Biochemistry, Materials, Energy, Medicinal Chemistry) have been removed.
HL · 240hSL · 150h
HL & SL
Levels
20%
IA Weight
240h
HL Hours
Past Papers Archive
Browse IB Chemistry past papers
View the normalized archive for Chemistry, organized by session and file type.
Syllabus Topics
Official topic breakdown with approximate teaching hours.
| Topic | SL Hours | HL Hours |
|---|---|---|
| Structure 1: Models of the Particulate Nature of Matter | 14h | 20h |
| S1.1 Introduction to the Particulate Nature of Matter | 2h | 3h |
| S1.2 The Nuclear Atom | 3h | 4h |
| S1.3 Electron Configurations (AHL: sub-shells, orbital theory) | 3h | 5h |
| S1.4 Counting Particles by Mass: The Mole | 4h | 5h |
| S1.5 Ideal Gases | 2h | 3h |
| Structure 2: Models of Bonding and Structure | 22h | 34h |
| S2.1 The Ionic Model | 5h | 8h |
| S2.2 The Covalent Model (AHL: VSEPR, hybridisation, delocalization) | 9h | 14h |
| S2.3 The Metallic Model | 4h | 5h |
| S2.4 From Models to Materials (polymers, liquid crystals, nanomaterials) | 4h | 7h |
| Structure 3: Classification of Matter | 24h | 36h |
| S3.1 The Periodic Table — Trends and Reactivity (AHL: d-block, complex ions) | 12h | 18h |
| S3.2 Functional Groups: Organic Chemistry (AHL: mechanisms, NMR, IR) | 12h | 18h |
| Reactivity 1: What Drives Chemical Reactions? | 14h | 26h |
| R1.1 Measuring Enthalpy Changes | 5h | 7h |
| R1.2 Energy Cycles in Reactions (Hess's Law, Born-Haber cycle AHL) | 5h | 8h |
| R1.3 Energy from Fuels | 4h | 4h |
| R1.4 Entropy and Spontaneity — HL only (Gibbs free energy)HL only | — | 7h |
| Reactivity 2: How Much, How Fast, How Far? | 22h | 30h |
| R2.1 The Amount of Chemical Change (stoichiometry, limiting reagents) | 6h | 8h |
| R2.2 The Rate of Chemical Change (AHL: Arrhenius, mechanisms, activation energy) | 9h | 12h |
| R2.3 The Extent of Chemical Change (equilibrium, Le Chatelier's, Kc AHL: Kp) | 7h | 10h |
| Reactivity 3: Mechanisms of Chemical Change | 14h | 34h |
| R3.1 Proton Transfer Reactions (acids/bases, pH, buffers AHL) | 6h | 13h |
| R3.2 Electron Transfer Reactions (redox, electrochemistry, standard electrode potentials AHL) | 5h | 11h |
| R3.3 Electron Sharing Reactions (homolytic cleavage, radical reactions) | 1h | 4h |
| R3.4 Electron-Pair Sharing Reactions (nucleophilic substitution, elimination, addition) | 2h | 6h |
| Total | 150h | 240h |
Assessment Structure
External Assessment
Paper 1 (combined MCQ + data-based, 36%). Paper 2 (structured short-answer and extended-response, 44%). Scientific Investigation / IA (20%). Calculators are now permitted in Paper 1. The old Paper 3 with optional topics has been removed entirely.
Internal Assessment — Scientific Investigation
HL: 20%SL: 20%
A student-designed laboratory investigation (max 3,000 words). Assessed on Research Design, Data Analysis, Conclusion, and Evaluation. A clear, focused research question and well-controlled variables are essential.
Exam Tips for IB Chemistry
1
Master S1.4 (The Mole) first — stoichiometry underpins every topic in the course
2
For HL R1.4 Entropy: understand ΔG = ΔH − TΔS deeply — it connects thermodynamics across all topics
3
Draw reaction mechanisms in R3.3 and R3.4 step by step with curly arrows — partial marks awarded
4
R3.1 (acids/bases) and R3.2 (redox) are the most calculation-heavy HL topics — practise daily
5
In the IA, ensure your research design section explains why your method controls the key variable
Grade Boundaries
View all subjects →| Session | Level | Grade 7 | Grade 6 | Grade 5 | Grade 4 | Grade 3 | Grade 2 | Max |
|---|---|---|---|---|---|---|---|---|
| May 2024 | HL | 76 | 64 | 52 | 40 | 27 | 15 | 100 |
| May 2024 | SL | 73 | 61 | 50 | 38 | 26 | 14 | 100 |
Grade boundaries shown are percentages. Actual boundaries vary by session and are set after grading. Use the score calculator →
Predict your IB Chemistry grade
Enter your component marks and see your predicted final grade based on grade boundaries.
Related IB Subjects
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HLSL
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Physics
HLSL
Engineering, physics, aerospace, and computer science university applications.
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Computer science, software engineering, and data science university applications.
Environmental Systems & Societies
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Students wanting a science credit with a humanities or sustainability focus.
Frequently Asked Questions
What topics are in IB Chemistry?
IB Chemistry covers Structure 1: Models of the Particulate Nature of Matter, S1.1 Introduction to the Particulate Nature of Matter, S1.2 The Nuclear Atom, S1.3 Electron Configurations (AHL: sub-shells, orbital theory), S1.4 Counting Particles by Mass: The Mole, S1.5 Ideal Gases, Structure 2: Models of Bonding and Structure, S2.1 The Ionic Model, S2.2 The Covalent Model (AHL: VSEPR, hybridisation, delocalization), S2.3 The Metallic Model, S2.4 From Models to Materials (polymers, liquid crystals, nanomaterials), Structure 3: Classification of Matter, S3.1 The Periodic Table — Trends and Reactivity (AHL: d-block, complex ions), S3.2 Functional Groups: Organic Chemistry (AHL: mechanisms, NMR, IR), Reactivity 1: What Drives Chemical Reactions?, R1.1 Measuring Enthalpy Changes, R1.2 Energy Cycles in Reactions (Hess's Law, Born-Haber cycle AHL), R1.3 Energy from Fuels, R1.4 Entropy and Spontaneity — HL only (Gibbs free energy), Reactivity 2: How Much, How Fast, How Far?, R2.1 The Amount of Chemical Change (stoichiometry, limiting reagents), R2.2 The Rate of Chemical Change (AHL: Arrhenius, mechanisms, activation energy), R2.3 The Extent of Chemical Change (equilibrium, Le Chatelier's, Kc AHL: Kp), Reactivity 3: Mechanisms of Chemical Change, R3.1 Proton Transfer Reactions (acids/bases, pH, buffers AHL), R3.2 Electron Transfer Reactions (redox, electrochemistry, standard electrode potentials AHL), R3.3 Electron Sharing Reactions (homolytic cleavage, radical reactions), R3.4 Electron-Pair Sharing Reactions (nucleophilic substitution, elimination, addition). HL students study additional depth and some HL-only extensions. Total teaching hours: HL 240, SL 150.
How is IB Chemistry assessed?
Paper 1 (combined MCQ + data-based, 36%). Paper 2 (structured short-answer and extended-response, 44%). Scientific Investigation / IA (20%). Calculators are now permitted in Paper 1. The old Paper 3 with optional topics has been removed entirely. The Internal Assessment (Scientific Investigation) counts for 20% of the final grade at SL and 20% at HL.
What is the IB Chemistry IA?
The IB Chemistry IA is the Scientific Investigation. A student-designed laboratory investigation (max 3,000 words). Assessed on Research Design, Data Analysis, Conclusion, and Evaluation. A clear, focused research question and well-controlled variables are essential. It accounts for 20% of the final grade at SL and 20% at HL.
Should I take IB Chemistry HL or SL?
Take HL if Chemistry is relevant to your university course (Engineering, medicine, pharmacy, and applied sciences university applications.), or if you are genuinely strong in the subject. HL adds 90 extra hours of content and deeper examination requirements. SL is suitable if you need the subject for the diploma but it is not your primary focus.