Elements and the periodic table

Periodic table

A table which shows all the elements arranged in rows and coloumns. Elements with similar properties are grouped together

Element

A pure substance made of only one kind of atom

Atom

Basic unit of matter

Compound

A group of two or more atoms strongly joined together

Metal qualities

Shiny, hard, malleable, good conductors of heat and electrictiy

Molecule

pure substances made from atoms of two or more elements chemically joined together

Chemical formula

A formula that shows the elements present in a compound and their relative proportions

Chemical symbol

The one or two letter code for elements used by scientists in all countries (e.g, Au=gold)

Period

Row of the periodic table

Group

A coloumn on the periodic table

Chemical reaction

A change in which a new substance is formed. Atoms are rearranged and join together differently