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

A sea of electrons

describe

Try it yourself

Which statement describes metallic bonding?

describe: give the features or what happens.

Choose one answera.Positive ions attracted to negative ions between themb.Positive ions attracted to a sea of delocalised electronsc.Pairs of electrons shared between two neighbouring atomsd.Weak forces that hold layers of metal atoms together

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Scope and sources

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

Giant covalent and metallic structures (2.6 Core 1–2, Supplement 3–4; 2.7 Supplement 1–2): the giant covalent structures of diamond and graphite and their uses in cutting tools, as a lubricant and as an electrode, the giant covalent structure of silicon(IV) oxide and its similarity in properties to diamond, metallic bonding as the attraction between positive ions in a giant metallic lattice and a sea of delocalised electrons, and the electrical conductivity, malleability and ductility of metals. Simple molecules, ionic lattices, alloys, the uses of metals and electrolysis are left to other modules.

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

Official Cambridge syllabus