AQA GCSE Chemistry key terms

The volume occupied by one mole of a gas at specified temperature and pressure. At RTP it is $24\,\text{dm}^3\text{/mol}$.

The amount of substance containing the same fixed number of particles as one mole of any other substance; its unit is mol.

A formula showing the numbers of each type of atom in a molecule, but not how they are bonded.

The three-dimensional arrangement of atoms bonded together in a molecule.

A group of atoms joined by covalent bonds that exists as a separate unit.

The relative amounts in moles of the substances taking part in a reaction.

Melted and in the liquid state.

Existing as individual atoms rather than as molecules containing two or more bonded atoms.

A small molecule that can join with others to form a polymer.

A number written before a chemical formula that multiplies every atom in that formula.

A unit of length equal to one billionth of a metre: $1\ \text{nm}=1\times10^{-9}\ \text{m}$.

A structure between 1 nm and 100 nm in size, typically containing of the order of a few hundred atoms.

A material made from, or containing, particles between 1 nm and 100 nm in size.

The study and use of structures whose dimensions are between 1 nm and 100 nm.

A substance or source of energy obtained from the Earth, oceans or atmosphere and used by humans.

An equation showing only the ions that undergo chemical change in a reaction.

Having no overall electrical charge because positive and negative charges balance.

A reaction in which an acid reacts with a base or alkali; hydrogen ions and hydroxide ions form water in an acid–alkali neutralisation.

A solution with pH 7, so it is neither acidic nor alkaline.

A particle with no electrical charge found in an atom's nucleus.

An element in the far-right group of the periodic table whose atoms have a stable, full outer electron shell and are therefore very unreactive.

The arrangement of electrons found in a Group 0 atom, with a complete outer electron shell.

A system from which matter, including a gas, can enter or leave during a reaction.

An element that does not react to form positive ions.

A cell designed to be used until a reactant is used up, after which its reaction cannot be usefully reversed by charging.

A fertiliser containing compounds that supply nitrogen, phosphorus and potassium.

A model in which an atom has a central nucleus containing protons and neutrons, with electrons around it.