All subjects

Select a subject from the left to view available exam boards and resources

Related: Past Papers Topical Questions IGCSE Physics AS Mathematics A2 Physics Grade Boundaries Command Words

2. Atoms, Elements & Compounds

Cambridge IGCSE Chemistry (0620) · 13 topics

Elements, Compounds & Mixtures

Pure Substances and Mixtures All matter can be classified as either pure substances (elements or compounds) or mixtures. Understanding the differences between…
Atomic Structure

The Atom Atoms are the basic building blocks of all matter. Everything around us is made of atoms, and understanding their structure is fundamental to…
Electronic Configuration

Electron Shells Electrons in atoms are arranged in shells (also called energy levels) around the nucleus. Understanding how electrons are arranged is crucial…
Isotopes

What are Isotopes? Not all atoms of the same element are identical. Isotopes are atoms of the same element that have different numbers of neutrons. Isotopes…
Ions & Ionic Bonds

What are Ions? Atoms can gain or lose electrons to become charged particles called ions. Understanding ions is essential for understanding chemical bonding and…
Ionic Bonds & Lattice Structure

Ionic Lattice Structure Ionic Lattice A regular, repeating three-dimensional arrangement of ions held together by strong electrostatic forces of attraction…
Properties of Ionic Compounds

Overview of Ionic Compound Properties Ionic compounds share a set of characteristic physical properties that arise from their giant ionic lattice structure.…
Covalent Bonds

What is a Covalent Bond? Covalent Bond A strong bond formed when two atoms share a pair of electrons. Each atom contributes one electron to the shared pair.…
Molecules & Compounds

What is a Molecule? Molecule A group of two or more atoms chemically bonded together by covalent bonds. Molecules can contain atoms of the same element or…
Properties of Simple Molecular Compounds

Overview Simple molecular compounds have characteristic physical properties that can be explained by their structure and bonding. Understanding the difference…
Diamond & Graphite

Giant Covalent Structures Giant Covalent Structure A continuous network of atoms bonded together by strong covalent bonds throughout the entire structure. Also…
Silicon(IV) Oxide

What is Silicon(IV) Oxide? Silicon(IV) Oxide (SiO₂) A giant covalent structure where each silicon atom is bonded to four oxygen atoms, and each oxygen atom is…
Metallic Bonding

What is Metallic Bonding? Metallic Bonding The strong electrostatic attraction between positive metal ions (cations) and the 'sea' of delocalized electrons that…