The atomic model

In 1932, James Chadwick discovered the neutron – a particle with no charge in the nucleus of the atom.

Structure of a carbon atom, with a proton, neutron and electron labelledThe modern model of the atom.

Today, scientists use an atomic model that has a central, positively-charged nucleus that contains:

  • positively-charged protons
  • neutral neutrons

Negatively-charged electrons orbit the nucleus in shells.

An atom’s nucleus gives it most of its mass.