AQA GCSE Chemistry key terms

The representative group of ions shown by the formula of an ionic substance, such as NaCl.

The reaction in which reactants form products as the equation is written from left to right.

A carbon-containing fuel formed from the buried remains of ancient organisms over millions of years; coal, crude oil and natural gas are examples.

A group of hydrocarbons from crude oil whose molecules have similar numbers of carbon atoms and similar boiling points.

Separating a mixture of miscible liquids with different boiling points using a fractionating column.

The change of state from a liquid to a solid.

Water with a low concentration of dissolved substances, such as rainwater collected in the ground, lakes and rivers.

A cell that produces a potential difference by reacting fuel and oxygen supplied from outside it.

A molecule made only of carbon atoms joined into a hollow shape, usually based on hexagonal rings.

All stages associated with something, from obtaining materials and making it through its use to its final disposal.

A formula showing every atom and every covalent bond in a molecule.

A group of atoms within a molecule that determines its characteristic chemical reactions.

Coating iron or steel with zinc to protect it from rusting.

A giant structure in which many atoms are joined by a continuous network of strong covalent bonds.

A regular, repeating giant structure made from positive and negative ions.

A very large, repeating arrangement of particles joined by bonding throughout the structure rather than separated into individual molecules.

A reduction in the amount of radiation reaching Earth's surface because particulates in the atmosphere block or scatter some of it.

The increase in Earth's average surface temperature over a long period.

A wooden splint whose flame has been blown out but whose hot tip continues to glow.

The change in the vertical-axis value divided by the change in the horizontal-axis value.

A single, one-atom-thick layer of graphite in which carbon atoms form a sheet of hexagonal rings.

The natural process in which atmospheric greenhouse gases reduce the rate at which energy escapes to space, maintaining Earth at a temperature high enough to support life.

A gas that absorbs infrared radiation emitted by Earth and transfers energy to the surroundings, warming the atmosphere.

A vertical column of the periodic table whose elements have related properties. For Groups 1–7, the group number equals the number of outer-shell electrons.

An element in the first column of the periodic table; the Group 1 elements are also called the alkali metals.

An industrial process in which nitrogen and hydrogen react under controlled conditions to manufacture ammonia.

The place and conditions in which an organism lives and obtains the resources it needs.