IB Chemistry — Syllabus & Revision Notes
BETADiploma Programme Chemistry, 2025-2030 syllabus (first assessment 2025) — the two organising concepts, Structure and Reactivity, with every topic and subtopic tagged for Standard and Higher Level.
What is IB Chemistry?
IB Chemistry is one of the Diploma Programme’s group 4 science subjects: a two-year course taken at either Standard Level (SL) or Higher Level (HL) and examined at the end of the second year. The 2025-2030 syllabus (first exams 2025) is built around two big organising ideas — Structure (how matter is built up, from particles to bonding to the classification of substances) and Reactivity (how and why chemical change happens: energetics, rates, equilibrium and reaction mechanisms).
SL and HL share the same structure of topics, but HL goes further: one topic is HL-only (entropy and spontaneity) and most other topics carry additional HL material — about 180 hours of taught content at HL against 110 at SL. SL and HL candidates sit separate exam papers: HL papers include the extra material, while SL papers draw only on SL content. Both levels are graded 1–7, and every paper is sat with the official data booklet on the desk — so revision is less about memorising constants and more about knowing how to apply them.
| Assessment | SL | HL | Weight |
|---|---|---|---|
| Paper 1 — 1A multiple choice + 1B data-based | 55 marks · 1h 30 | 75 marks · 2h | 36% |
| Paper 2 — short-answer and extended response | 50 marks · 1h 30 | 90 marks · 2h 30 | 44% |
| Internal assessment — the scientific investigation | marked by your teacher, moderated by the IB | 20% | |
The syllabus map below lists every topic and subtopic with its level badge — SL & HL shared, SL & HL +HL with HL extensions, HL only. Each topic with notes links to revision notes that use the data booklet’s own notation, and pages with HL material have an SL/HL switch so you only revise what your paper can ask.
S Structure
How matter is built up: particles, atoms, bonding and the classification of substances.
S1 — Models of the particulate nature of matter
- Elements, compounds and mixtures
- Separation techniques
- States of matter and the kinetic molecular theory
- Temperature and the Kelvin scale
- Protons, neutrons and electrons
- Isotopes and relative atomic mass
- Mass spectrometry (HL)
- Emission spectra
- Energy levels and sublevels
- Electron configurations (Aufbau, Hund, Pauli)
- Atomic orbitals (s and p)
- Ionization energy and the convergence limit (HL)
- Successive ionization energies (HL)
- The mole and the Avogadro constant
- Relative atomic and formula mass
- Molar mass and the mole
- Empirical and molecular formulae
- Molar concentration
- Avogadro's law and gas volumes
- The ideal gas model
- Real versus ideal gases
- Molar volume of a gas
- The ideal gas equation and gas laws
S2 — Models of bonding and structure
- Formation of ions
- Ionic bonding and formulae
- Ionic lattices and their properties
- Lattice enthalpy as a measure of bond strength
- Covalent bonds and Lewis formulas
- Bond order, length and strength
- Coordination bonds
- VSEPR and molecular geometry
- Bond and molecular polarity
- Covalent network solids and allotropes of carbon
- Intermolecular forces
- Chromatography and Rf values
- Resonance and delocalization (HL)
- Benzene (HL)
- Expanded octets (HL)
- Formal charge (HL)
- Sigma and pi bonds (HL)
- Hybridization (HL)
- Metallic bonding
- Properties and bond strength of metals
- Transition elements and delocalized d-electrons (HL)
- The bonding continuum and bonding triangle
- Predicting properties from the bonding triangle
- Alloys
- Polymers and plastics
- Addition polymers
- Condensation polymers (HL)
S3 — Classification of matter
- Periods, groups and blocks
- Electron configuration and the periodic table
- Periodic trends
- Group 1 and group 17 trends
- Acid-base character of oxides
- Oxidation states
- Discontinuities in ionization energy (HL)
- Transition elements (HL)
- Variable oxidation states (HL)
- Coloured complexes (HL)
- Representing organic molecules
- Functional groups
- Homologous series
- Trends in physical properties
- IUPAC nomenclature
- Structural isomers
- Stereoisomers (HL)
- Mass spectrometry (HL)
- Infrared spectroscopy (HL)
- Proton NMR spectroscopy (HL)
- Combining analytical techniques (HL)
R Reactivity
How and why chemical change happens: energetics, rates, equilibrium and reaction mechanisms.
R1 — What drives chemical reactions?
- Energy transfer in reactions
- Endothermic and exothermic reactions
- Energy profiles
- Standard enthalpy change
- Calorimetry and q = mcΔT
- Bond enthalpies
- Hess's law
- Enthalpy of combustion and formation (HL)
- Hess's law calculations (HL)
- Born-Haber cycles (HL)
- Combustion reactions
- Incomplete combustion
- Fossil fuels and carbon dioxide
- Biofuels
- Fuel cells
- Entropy
- Gibbs energy
- Spontaneity
- Gibbs energy and equilibrium
R2 — How much, how fast and how far?
- Chemical equations
- Mole ratios and stoichiometry
- Limiting and excess reactants
- Theoretical and percentage yield
- Atom economy
- Rate of reaction
- Collision theory
- Factors affecting rate
- Activation energy and the Maxwell-Boltzmann distribution
- Catalysts
- Reaction mechanisms and the rate-determining step (HL)
- Molecularity (HL)
- Rate equations and order of reaction (HL)
- The rate constant (HL)
- The Arrhenius equation (HL)
- Dynamic equilibrium
- The equilibrium constant expression
- The magnitude of K and the extent of reaction
- Le Chatelier's principle
- The reaction quotient Q (HL)
- Equilibrium calculations (HL)
- Equilibrium and Gibbs energy (HL)
R3 — What are the mechanisms of chemical change?
- Bronsted-Lowry acids and bases
- Conjugate acid-base pairs
- Amphiprotic species
- The pH scale
- The ionic product of water Kw
- Strong and weak acids and bases
- Neutralization reactions
- pH curves
- Ka, Kb, pKa and pKb (HL)
- Salt hydrolysis (HL)
- Acid-base indicators (HL)
- Buffer solutions (HL)
- Oxidation and reduction
- Oxidation states
- Half-equations and redox equations
- Reactivity and displacement reactions
- Voltaic cells
- Secondary (rechargeable) cells
- Electrolytic cells
- Oxidation and reduction of organic compounds
- Standard electrode potentials (HL)
- Standard cell potential and Gibbs energy (HL)
- Electrolysis of aqueous solutions (HL)
- Electroplating (HL)
- Radicals
- Homolytic fission
- Radical substitution of alkanes
- Nucleophiles and nucleophilic substitution
- Heterolytic fission
- Electrophiles
- Electrophilic addition to alkenes
- Lewis acids and bases (HL)
- Coordination bonds and complex ions (HL)
- Nucleophilic substitution: SN1 and SN2 (HL)
- Leaving groups and reaction rate (HL)
- Electrophilic addition mechanisms (HL)
- Electrophilic substitution of benzene (HL)