Chemistry key terms

Zeros written after the final non-zero digit; in a decimal value, they can show the precision with which the value is reported.

A metal in the central region of the periodic table; many transition elements form ions with different charges, form coloured compounds and are useful as catalysts.

A metal from the central block of the periodic table; transition metals typically have high melting points and densities, form coloured compounds and show catalytic activity.

A general pattern showing how a property changes across a series of elements.

A covalent bond formed from three shared pairs of electrons.

A covalent bond containing three shared pairs of electrons.

Cloudiness caused by fine particles suspended in a liquid.

A flat representation with height and width but no actual depth.

Radiation from sunlight that sunscreen is designed to stop reaching the skin.

The range within which the true value is reasonably expected to lie, arising from limitations in measurements, data, assumptions or models.

An element found in nature without being chemically combined with another element.

An effect that was not intended when a technology or process was introduced.

A result that distinguishes one possible ion from all the other ions being considered.

An agreed standard used to express the magnitude of a quantity, such as grams for mass or cubic centimetres for volume.

Changing a measurement from one unit to an equivalent value in another unit.

A standard letter or group of letters representing a unit, such as g for gram or J for joule.

A mixture of indicators that produces a range of colours and is used with a colour chart to estimate pH.

A solution containing one or more species whose identities are to be determined.

A molecule containing a carbon–carbon double bond, so it has fewer hydrogen atoms than the corresponding alkane.

A hydrocarbon containing at least one carbon–carbon double bond.

The combining power of an element, shown by how its atoms combine with atoms of other elements.

Whether a method and its data measure what the investigation is intended to measure.

One of the deliberately selected settings of the independent variable, such as a particular concentration or temperature.

A decision influenced by the importance people give to different effects, rather than determined by measurement alone.

Principles or priorities that influence what a person or group considers important, desirable or acceptable.

The change of state from a liquid to a gas.

A letter or symbol representing a quantity whose value may vary.

Whether a process is practical and worthwhile when its resources, costs, demand and environmental effects are considered.

Able to work successfully in practice at an acceptable economic and environmental cost.

A measure of how much a fluid resists flowing; a more viscous liquid flows less easily.