A species of atom can have some atoms with different numbers of neutrons a. When the number of neutrons exceeds the number of protons, the neutrons are unstable. In large molecules a number of neutrons even less than the number of protons may be unstable 2. A lone neutron would become unstable in about 8 minutes 3. An unstable neutron breaks into a proton, beta particle and energy 4.
All electromagnetic waves travel at the speed of light and have no mass.
B. Long wave-length electromagnetic waves have less energy eg. They thus produce heat in a solution, but don't produce ions. The electrons don't make beta particles, but stick to one part of the broken molecule thus one part has a plus charge and one a minus charge. E. Visible light waves are just strong enough to change very delicate molecules like rhodopsin, but not enough to change very many molecules. The eye uses this molecular change to detect the light.