1. IP2.28.3 Simple introduction to decay Simple introduction to decay

2. IP2.28.3 Simple introduction to decay  Some atomic nuclei are unstable and they undergo a process of radioactive decay. In this process the nucleus loses energy and emits some ionising particles or radiation.  The nucleus is then in a lower and more stable state.

3. IP2.28.3 Simple introduction to decay There are three different type of ionising particle or radiation. They were named alphabetically (using the Greek alphabet):  Alpha particles (α)  Beta particles (β)  Gamma radiation (γ)

4. IP2.28.3 Simple introduction to decay  The size, charge and nature of each type of radiation are:  Alpha particles (α)– 2 protons and 2 neutrons +ve charge  Beta particles (β) – high speed electron –ve charge  Gamma radiation (γ) – high energy electromagnetic wave – no charge.

5. IP2.28.3 Simple introduction to decay  Why does radioactive decay occur?  Some atoms are unstable – with a slight rearrangement of the particles in the atom it would be able to release some energy and exist in a lower energy state.  In radioactive decay this process is spontaneous. It does not need anything to trigger it to occur – it just happens.  Think of it like an avalanche. Snow builds up on a mountain side and everything looks okay, until an avalanche occurs. The snow was in an unstable state. The avalanche releases a large amount of energy and the snow ends up at the bottom of the mountain in a much lower energy state.