IB Diploma Programme Chemistry: Subject Overview

As one of the three natural sciences in the IB Diploma Programme, Chemistry is primarily concerned with identifying patterns that help explain matter at the microscopic level, allowing matter’s behaviour to be predicted and controlled at a macroscopic level. The subject emphasizes representative models and explanatory theories, both relying heavily on creative but rational thinking.

Scientific inquiry

Integral to the DP Chemistry experience is learning through scientific inquiry, both in the classroom and the laboratory. Students engage with topical scientific issues, examining scientific knowledge claims in a real-world context, and this inquiry-based approach runs through practical work, the collaborative sciences project and the internal assessment alike, rather than being confined to a single component of the course.

Aims

Through the overarching theme of the nature of science, the course aims to enable students to:

1. develop conceptual understanding connecting different areas of the subject, and other DP sciences subjects
2. acquire and apply a body of knowledge, methods, tools and techniques that characterize science
3. develop the ability to analyse, evaluate and synthesize scientific information and claims
4. develop the ability to approach unfamiliar situations with creativity and resilience
5. design and model solutions to local and global problems in a scientific context
6. develop an appreciation of the possibilities and limitations of science
7. develop technology skills in a scientific context
8. develop the ability to communicate and collaborate effectively
9. develop awareness of the ethical, environmental, economic, cultural and social impact of science.

How it’s assessed

DP Chemistry follows the same overall assessment model as the other DP sciences, combining external examination with an individual internal assessment, at both Standard Level and Higher Level. Paper 1 is weighted at 36% of the final grade and includes multiple-choice questions alongside short-answer and data-based questions spanning the syllabus; Paper 2 is weighted at 44% and includes multiple-choice questions alongside short-answer and extended-response answers that draw together structure and reactivity concepts across topics. (This guide’s own extraction stops before the assessment outline pages, so the exact split of question types within each paper has not been verified directly against the guide – check the current subject guide’s assessment section for the definitive breakdown.) Between them, the two papers account for 80% of the final mark, with SL and HL differing in exam length and mark totals rather than in this weighting split.

The remaining 20% is the internal assessment – an independent scientific investigation that students design, carry out and report on individually, submitted as a written report of up to 3,000 words. It is distinct from the interdisciplinary collaborative sciences project undertaken with peers across group 4 subjects, which develops investigative and teamwork skills but is not itself part of the internally assessed component.

The chemistry syllabus itself is organized around two linked organizing concepts – structure and reactivity – reflecting the idea that the structure of matter determines how it reacts, and that those reactions in turn transform structure. Both Paper 1 and Paper 2 draw questions from across this structure-and-reactivity framework rather than testing each syllabus topic as a standalone block, which is one reason the two papers are weighted so closely together at 36% and 44% of the final grade.

The Structure and Reactivity strands

The syllabus is organised into two linked strands, each split into three numbered components. The Structure strand covers models of the particulate nature of matter – the nuclear atom, electron configurations, the mole and ideal gases – models of bonding and structure across ionic, covalent and metallic bonding, and the classification of matter through the periodic table and organic functional groups. The Reactivity strand covers what drives chemical reactions, including enthalpy change and energy cycles; how much, how fast and how far a reaction proceeds, covering stoichiometry, rate and equilibrium; and, in its third component, further reaction mechanisms building on structure and bonding concepts from earlier in the course. Both strands are examined together rather than as separate blocks, since Paper 1 and Paper 2 both draw questions from across the whole structure-and-reactivity framework, which is one reason the two papers are weighted so closely together at 36% and 44% of the final grade rather than one paper being dedicated exclusively to one strand.

What Structure and Reactivity each ask

The syllabus deliberately separates two different kinds of chemical question: Structure asks what matter is built from and how it is arranged, while Reactivity asks why and how matter changes. The two are not independent, though – Reactivity 3, on reaction mechanisms, draws most heavily on everything covered in Structure 1 and Structure 2, since reasoning about electron-transfer or electron-sharing mechanisms requires a secure grip on electron configurations and bonding models covered earlier in the course. This is why revising Structure and Reactivity as two parallel, connected tracks rather than strictly in numerical order tends to work better than treating the six syllabus components as isolated topics – a question on entropy and spontaneity, for instance, still expects fluent reasoning about particle behaviour from Structure 1, even though entropy itself sits within Reactivity.

HL-only content across the syllabus

HL students study additional content within all six syllabus components, though the extra depth is not spread evenly: Structure 1 gains 4 hours (17 to 21), Structure 2 gains 10 hours (20 to 30), Structure 3 gains 15 hours (16 to 31), Reactivity 1 gains 10 hours (12 to 22, split evenly between energy cycles and entropy and spontaneity), Reactivity 2 gains 10 hours (21 to 31), and Reactivity 3 gains 21 hours (24 to 45). These are the points where SL-level revision habits most often under-prepare HL candidates, since it is easy to assume the additional depth concentrates in only a few components when in practice every component carries some HL-only material. Confirming exactly which sub-topics within each component count as HL-only is worth doing early in the course rather than discovering the gap only once exam preparation is already under way.

Source

International Baccalaureate Organization, Chemistry guide, Diploma Programme, first assessment 2025 (published February 2023, updated May 2023) – copy consulted via a school-hosted mirror, not ibo.org.