Gas which burns in air with an explosive "pop".

Pale green poisonous gas.

Reactive metal which (in small quantities) melts but does not burn when added to cold water .

Dark red liquid non-metal.

Dense metal which is so soft it leaves a mark on paper.

Very reactive metal which bursts into a lilac-coloured flame when added to cold water.

Reactive metal with a low density; it appears unreactive because its surface has a hard insoluble layer of oxide.

Least dense and first member of the halogens.

Colourless gas which relights a glowing splint.

The commonest element in the earth's crust; the common form of its oxide is sand.