What is the difference between radioactive decay and radioactivity?

What is the difference between alpha and beta decay versus gamma decay?

• Answer:

  Alpha and beta decay of an atom involves the loss of particles from the nucleus. Alpha decay means the loss of two neutrons and two protons from the nucleus, whereas beta decay requires a neutron to decay to an electron (which leaves the atom at high speed) and a proton (which stays in the nucleus). In both cases the result of the decay is a change in the atom to give another element altogether. Alpha decay gives an element with an atomic number that is two lower than the starting element; Beta decay gives an element with an atomic number that it one higher than the original element. Gamma decay is 'simply' the loss of excess energy from the nucleus - the gamma ray is simply energy in the form of electromagnetic radiation - and the nature of the element is unchanged from before it emits the gamma ray. Gamma radiation often accompanies beta or alpha emission. For example, when 60Co undergoes beta decays to 60Ni, the 60Ni is in a high energy state and loses the excess energy by emitting two gamma rays.