Different types of chemical substance

Can you recognise pure elements, pure compounds, and mixtures?

  • an element contains just one type of atom
  • a compound contains two or more types of atom joined together
  • a mixture contains two or more different substances that are not joined together
  • the different substances in a mixture can be elements or compounds

The table shows some examples:

Table with examples and diagrams of a pure element (oxygen), pure compound (carbon dioxide), mixture of elements (oxygen and helium), mixture of compounds (alcohol and water), mixture of elements and compounds (air)

Notice that the different substances in a mixture can be single atoms, molecules of elements or molecules of compounds.

Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.