Ages 12–13: Educational resources

What's an atom?

Atoms make everything around you. They are extremely small. For instance, a human hair is made up of trillions and trillions of atoms!

Atoms have three important parts: electrons, protons and neutrons.

Protons and neutrons are in the centre of the atom. We call this the nucleus of the atom.

Electrons spin around the nucleus in paths called orbitals.


When scientists discovered all this spinning going on inside of atoms, they realized that what appears to be solid matter is mostly just empty space.

Depending on the number of protons in the nucleus, we get different, unique elements. For instance, copper, which is used to make 1 cent coins in Canada, always has 29 protons in its nucleus.

There are a total of 94 elements found in nature. These elements combine to form molecules. For instance, the water you drink (H2O) is made of one atom of oxygen and two atoms of hydrogen.

To help you see the big picture, think of it like this:

  • atoms create elements
  • elements create molecules
  • molecules create cells
  • cells form tissue and organs for people and animals, for instance

NEXT: Nuclear energy