Radioactive substances

Radioactivity

The structure of the atom

Atoms are made up of two main parts, the nucleus and orbiting electrons.

The nucleus contains two types of particles called neutrons and protons. As protons, neutrons and electrons are the building blocks of atoms they're called sub-atomic particles.

Properties of sub-atomic particles

Particle     Relative mass            Relative charge  

Proton                    1                                             +1

Neutron               1                                                0

Electron     Almost…