Contents

States of matter

Atoms, elements and compounds

Stoichiometry

Electrochemistry

ElectrolysisBeing prepared
Electrolysis of solutions and electroplatingBeing prepared
Fuel cellsBeing prepared

Chemical energetics

Chemical reactions

Acids, bases and salts

Acids, bases and indicators
OxidesBeing prepared
Making saltsBeing prepared

The Periodic Table

Reading the tableBeing prepared
Group I: the alkali metalsBeing prepared
Group VII: the halogensBeing prepared
Transition elements and noble gasesBeing prepared

Metals

Metals and alloysBeing prepared
The reactivity seriesBeing prepared
CorrosionBeing prepared
Extracting metalsBeing prepared

Chemistry of the environment

WaterBeing prepared
FertilisersBeing prepared
Air quality and climateBeing prepared

Organic chemistry

Naming organic moleculesBeing prepared
Crude oil and alkanesBeing prepared
AlkenesBeing prepared
Alcohols and carboxylic acidsBeing prepared
PolymersBeing prepared

Experimental techniques and chemical analysis

Mixtures and separation
Measuring and planning experimentsBeing prepared
Crystallisation
Distillation
Paper chromatography
Choosing methods and checking purityBeing prepared
TitrationBeing prepared
Gas testsBeing prepared
Anion testsBeing prepared
Cation and flame testsBeing prepared

Part 2 of 2

Page 02

Why is chlorine 35.5?

calculate

Try it yourself

Boron has two isotopes. Calculate the relative atomic mass of boron. Give your answer to one decimal place.

calculate: work out the answer from the data.

Isotope	Mass number	Abundance (%)
boron-10	10	20
boron-11	11	80

Give your answer with its unit

Type numbers like 0.25 or 2.5x10^-3. Put the unit in its own box, for example g, cm3 or m/s. Leave the unit box empty if the quantity has no unit.

Relative atomic mass, Ar

Number

Unit

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Scope and sources

Cambridge IGCSE Chemistry 0620 · 2026–2028 v2 · Original learning materials.

Isotopes (2.3 Core 1–2, Supplement 3–4): isotopes as atoms of the same element with the same number of protons and different numbers of neutrons, symbols for atoms and ions such as ¹²₆C and ³⁵₁₇Cl⁻, why isotopes have the same chemical properties (the same number of electrons and the same electronic configuration), and how to calculate relative atomic mass from isotope masses and abundances. Relative atomic mass measured against carbon-12, relative molecular mass, radioactivity and mass spectrometry are left to other modules or are not in the course.

Apparatus, amounts and times in the experiment are illustrative. Real practical work follows a teacher-approved safety method.

Official Cambridge syllabus