Radioactivity

- Some isotopes have an unstable nucleus

- To become stable, the nucleus gives out radiation, which is called radioactive decay

• Completely random process

The activity is the rate at which a source of unstable nuclei decay

- Activity is measured in Becquerel (Bq) 1 Bq = 1 decay per second

- To measure activity of a radioactive source you can use a Geiger-Muller tube

The count rate is the number of decays recorded each second by a detector

4 types of radiation

- Alpha particle → 2 protons, 2 neutrons (same nucleus as helium)

- Beta particle → An electron which is ejected from the nucleus at high speed A beta particle is formed inside the nucleus when a neutron changes into a proton and an electron.

- Gamma ray → type of electromagnetic radiation from the nucleus

- Neutron