IB Chemistry for the 2026 examination sessions follows the course first assessed in 2025. The official syllabus is built around two organising concepts, Structure and Reactivity. These are divided into six named syllabus components, with selected additional content at HL.[1]
TL;DR The current course has two external papers. Paper 1 contains Paper 1A multiple-choice questions and Paper 1B data-based and experimental-work questions. Paper 2 contains short-answer and extended-response questions. The scientific investigation is worth 20 % at both SL and HL and has a maximum overall word count of 3,000 words.[1]
Last reviewed: 23 July 2026 against the current IB Chemistry curriculum page.
The experimental programme includes practical work, a collaborative sciences project, and the individual scientific investigation. The subject brief allocates 10 hours to the collaborative project and 10 hours to the scientific investigation at both levels.[1]
The official syllabus structure
Structure 1: Models of the particulate nature of matter
Official subtopics are:
Introduction to the particulate nature of matter
The nuclear atom
Electron configurations
Counting particles by mass: the mole
Ideal gases
The recommended allocation is 17 hours at SL and 21 hours at HL.[1]
Structure 2: Models of bonding and structure
Official subtopics are:
The ionic model
The covalent model
The metallic model
From models to materials
The recommended allocation is 20 hours at SL and 30 hours at HL.[1]
Structure 3: Classification of matter
Official subtopics are:
The periodic table: classification of elements
Functional groups: classification of organic compounds
The recommended allocation is 16 hours at SL and 31 hours at HL.[1]
Reactivity 1: What drives chemical reactions?
Official subtopics are:
Measuring enthalpy change
Energy cycles in reactions
Energy from fuels
Entropy and spontaneity (additional HL content)
The recommended allocation is 12 hours at SL and 22 hours at HL.[1]
Reactivity 2: How much, how fast and how far?
Official subtopics are:
How much? The amount of chemical change
How fast? The rate of chemical change
How far? The extent of chemical change
The recommended allocation is 21 hours at SL and 31 hours at HL.[1]
Reactivity 3: What are the mechanisms of chemical change?
Official subtopics are:
Proton transfer reactions
Electron transfer reactions
Electron sharing reactions
Electron-pair sharing reactions
The recommended allocation is 24 hours at SL and 45 hours at HL.[1]
These six components are the official public coverage map. Environmental, ethical, economic, and social contexts are part of the wider nature-of-science framing, but the public syllabus map does not define a separate Environmental Chemistry strand. Use Structure and Reactivity as the content owners.[1]
Assessment structure
Component
SL
HL
Weight
Paper 1
1.5 h
2 h
36 %
Paper 2
1.5 h
2.5 h
44 %
Scientific investigation
10 h
10 h
20 %
Paper 1
Paper 1 has two parts:
Paper 1A: multiple-choice questions
Paper 1B: data-based questions and questions on experimental work
Together, Paper 1A and Paper 1B account for 36 % of the final grade. Earlier versions of this page incorrectly listed 20 % and shorter paper times. Those figures belonged to an outdated or mixed assessment model and have been removed.[1]
Paper 2
Paper 2 contains short-answer and extended-response questions. It accounts for 44 % of the final grade. Earlier versions of this page incorrectly listed 40 % and 2 hours 15 minutes for both levels. The official first-assessment-2025 subject brief gives 1.5 hours at SL and 2.5 hours at HL.[1]
Scientific investigation
The scientific investigation is an open-ended task in which the student gathers and analyses data to answer a research question they formulate. The outcome is a written report with a maximum overall word count of 3,000 words.[1]
The public subject brief does not reproduce the full marking rubric. Use the current rubric and submission instructions supplied by your school or IB coordinator. Do not rely on older online advice that says there is no word limit or uses pre-2025 criterion names such as Personal Engagement and Exploration.
A source-backed study plan
Revise by the six official components
Build a checklist from Structure 1 to 3 and Reactivity 1 to 3. Within each component, practise moving between models, calculations, experimental evidence, and explanations.
Practise experimental reasoning
Experimental work is part of Paper 1B and the wider experimental programme. Revision should include uncertainty, data processing, method design, and evaluation rather than only reaction equations and calculations.
Treat Structure and Reactivity as connected
The IB curriculum page states the central relationship directly: structure determines reactivity, and reactivity transforms structure.[2] When revising a reaction, ask which structural feature drives it and what structural change results.
Confirm school-specific rules
The subject brief establishes the paper structure, time, weights, and investigation word limit. Calculator instructions, internal deadlines, authentication, and the detailed rubric should be checked with the current school guidance.
For Singapore university planning
Subject prerequisites vary by course. Current official examples include HL Chemistry plus HL Biology or HL Physics for medicine at NUS and NTU, while other science and engineering programmes publish different combinations. Do not assume that every science course requires both Biology and Chemistry, or that SL Chemistry satisfies a programme that names HL Chemistry.
Does current IB Chemistry have three external papers? No. The current first-assessment-2025 course has Paper 1 and Paper 2. Paper 1 is divided into parts 1A and 1B.[1]
What are the correct assessment weights? Paper 1 is 36 %, Paper 2 is 44 %, and the scientific investigation is 20 % at both SL and HL.[1]
Is there a word limit for the scientific investigation? Yes. The official subject brief gives a maximum overall word count of 3,000 words.[1]
Is Environmental Chemistry a third organising strand? No. The official course map uses Structure and Reactivity. Environmental contexts may support nature-of-science discussion and application, but they are not a third named syllabus strand in the current public brief.[1][2]
