Alpha, Gamma and Neutron Radiation

1. Alpha, Gamma and Neutron Radiation

2. 4 4 He  2 or 2 Alpha Radiation Alpha radiation is formed when an unstable nucleus decays, emitting an alpha particle. Alpha particles have an atomic mass of 4 and a relative charge of +2.

3. Properties of alpha particles • They are not as penetrating as beta particles but they are very ionising. • They are 8000 times heavier than beta particles. • They can easily remove electrons from atoms when they collide with due to their large +2 relative charge • They have short range in air (few cms)

4. When a radioactive atom emits an alpha particle, its mass number decreases by four and its atomic number decreases by two. Alpha Radiation () Alpha particles are commonly emitted from heavy nuclei which have a large number of protons and neutrons, e.g. α 226 222 4 Ra Rn + 88 86 2 Radium - unstable metal Radon - more stable gas Alpha particle Checking the atomic mass figures... 226 = 222 + 4 Checking the atomic number figures... 88 = 86 + 2

5.  0 0 Gamma Radiation As gamma rays are high energy electromagnetic waves, they have zero mass and zero charge. A gamma ray is written as: The gamma rays are weakly ionising, as they tend to pass througha substance. They are very penetrating. They have a very long range.

6.  0 0 60 60 Ni Ni + 28 28 How does a nucleus when gamma rays are emitted? When a gamma ray is emitted from an atom, it has no effect oneither the mass number or atomic number. It does however increase the stability of the nucleus, as it reduces its energy level.

7. 13 12 Be Be n + 4 4 Neutron Radiation (n) Neutron radiation is a type of ionising radiation which consists of free neutrons. As neutrons have no charge, they are not directly ionising. Because neutrons have no charge they are more penetrating than alpha radiation or beta radiation (in some cases gamma) Examples of an isotope which emit neutrons is beryllium-13: Neutron radiation causes the atomic mass to fall by one.