Most radioactive substances have many more particles in their nucleus. When an unstable nucleus decays, there are three ways that it can do so. Many radioactive substances emit a particles and b particles as well as g rays. Click the button. Alpha particles are made of 2 protons and 2 neutrons .
Alpha particles are relatively slow and heavy .
They have a low penetrating power - you can stop them with just a sheet of paper . Because they have a large charge, alpha particles ionise other atoms strongly. Click the button. This means that beta particles are the same as an electron . They are fast , and light .