Chemical symbols

Each element in the Periodic Table is represented by its own chemical symbol.

A chemical symbol has one or two letters, and it must always start with a capital letter. Any second letter must always be lower case.

For example, Mg is the correct symbol for magnesium, but mg, mG and MG are wrong. Take care to write chemical symbols correctly.

Table showing that capital M, lowecase g is correct but other variations of capitals and lowercase are wrong

Diatomic elements

The formulae for most elements is just their symbol. The exceptions are some non-metal elements known as diatomic elements . They contain two atoms of the same element covalently bonded together.

Diatomic elementMolecular formula
hydrogenH2
nitrogenN2
oxygenO2
fluorineF2
chlorineCl2
bromineBr2
iodineI2
astatineAt2
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The same chemical symbols are used all over the world, no matter which language is spoken, which makes them very useful.