Radioactive Decay

Alpha particles (α) consist of 2 neutrons and 2 protons (no electrons).

This is the same as a helium nucleus.

Alpha decay causes the mass number of the nucleus to decrease by four and the atomic number of the nucleus to decrease by two.

The overall charge of an alpha particle is +2.

If a nuclei has too many neutrons, a neutron will turn into a proton and emit a fast-moving electron. This electron is called a beta (β) particle.

A beta particle has a relative mass of zero. Beta decay causes the atomic number of the nucleus to increase by one and the mass number remains unchanged.

The charge of a beta particle is -1.

After emitting alpha/beta particles, nuclei still have a high amount of energy and need to 'cool down'.

So, often they will emit gamma rays (γ). These are electromagnetic (EM) waves.

Gamma ray emission causes no change in the number of particles in the nucleus meaning both the atomic number and mass number remain unchanged.

During 1986, a nuclear power plant in Ukraine experienced a critical failure in their safety measures. This resulted in a considerable amount of radioactive contamination.

This contamination included alpha, beta and gamma radiation.

Today, tourists can enter limited parts of Chernobyl.

All types of radioactive decay can be detected by a Geiger-Muller tube, or G-M tube.

The radiations ionise the gas inside and the resulting charged particles move across the chamber and get counted as charges rather like an ammeter.