Atoms

• Everything is made of atoms.
• They are the ‘building blocks of matter’.
• Atoms are very small - they have a radius of about 0.1 nanometers.
• They’re made up of a nucleus (which contains protons and neutrons) with electrons orbiting around it.

The definition of an atom is “the smallest part of an element that can exist”.

Subatomic particles

Atoms are made up of 3 types of subatomic particles (the things inside the atom itself):

• proton - positively charged particles found in the nucleus
• neutron - neutral particles found in the nucleus
• electron - negatively charged particles which orbit the nucleus

Models of the atom

There are lots of different ways we can model the atom.

The one that is most commonly used today is the Bohr model, which shows a small nucleus made up of protons and neutrons, with electrons orbiting around it in their own energy levels (called shells).