A compound is made from atoms which are chemically combined into molecules.

A molecule made from
three different atoms.

Each molecule in a compound can have one or more types of atoms in it. Because the atoms are actually joined together, you cannot separate the substances in a compound by hand, by filtering, or by any mechanical means.
Some examples of compounds, with their corresponding formulas:
  • Salt: NaCl (sodium Na and chlorine Cl)
  • Water: H2O (two hydrogen atoms H and an oxygen O)
  • Carbon Dioxide: CO2 (carbon C and two oxygens O)
  • Methane CH4 (carbon C and four hydrogens H)

Here's a close-up example. This might be a molecule of sugar:


Each sugar molecule is made up of three kinds of atoms stuck together in a certain pattern.
The substance 'sugar' is just a collection of many of these molecules:

'A Compound is made from molecules, which are chemical combinations of atoms of one or more varieties. A compound cannot be separated into different substances by mechanical means'


Elements | Compounds | Mixtures | Solutions

How Things Combine

Chemistry | Science | Worsley School

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