Chemistry key terms

A melting interval covering only a very small temperature range, characteristic of a pure substance.

The reduction in the attraction between the nucleus and an outer electron caused by electrons in inner shells.

A change in the position of equilibrium towards reactants, increasing their relative amount at the new equilibrium.

A change in the position of equilibrium towards products, increasing their relative amount at the new equilibrium.

An atom or group attached to the polymer backbone rather than forming part of the continuous backbone itself.

A reaction other than the expected reaction that uses some reactant and forms different products.

The importance or meaning of a result in its context. It depends on more than numerical size alone.

A digit that contributes to the stated precision of a measured or calculated value, counted from the first non-zero digit.

The number of meaningful digits used to express the precision of a measured or calculated value.

Shapes that have the same proportions but may be different sizes.

Separating a solvent from a solution by boiling it and then cooling its vapour to collect the liquid.

A single charged atom formed when an atom gains or loses electrons.

A substance made of separate, small molecules in which non-metal atoms are joined by covalent bonds.

A substance made from separate, relatively small molecules whose atoms are joined by covalent bonds.

A discrete group of atoms joined by strong covalent bonds.

A simplified representation in which small spheres stand for the atoms, ions or molecules in a substance.

A covalent bond containing one shared pair of electrons.

A covalent bond containing one shared pair of electrons.

A material or process that removes a substance faster than it is released; early rocks acted as sinks for atmospheric oxygen.

A discrete group of a relatively small number of atoms held together by covalent bonds.

A harmful mixture of gases and particles that accumulates in the air, often including pollutants formed through reactions involving nitrogen oxides.

A factor concerning communities or groups, such as public acceptance, access, fairness, employment or effects on quality of life.

Easy to cut or deform; alkali metals are soft enough to be cut with a knife.

A temperature at which a material becomes less rigid and more easily deformed; this does not necessarily mean that it melts.

A low-melting alloy used to join metal parts, traditionally made from lead and tin.

A state of matter in which particles are closely packed in a regular arrangement and vibrate about fixed positions.

The ability of a substance to dissolve in a particular solvent.

A rule used to predict whether an ionic compound will dissolve in water.

Able to dissolve in a particular solvent; here, the solvent is water.

An ionic compound that dissolves in water to form a solution containing mobile ions.