P5 - Radioactive Materials

• Isotopes are two or more forms of the same element that have different numbers of neutrons in their nuclei
• Proton number is the number of positively charged particles in the nucleus of an atom (also known as the atomic number)
• Nuclear equation refers to the summary of changes that take place during radioactive decay
• Beta particle is an electron emitted by some types of radioactive material, it has a negative charge (-1) and a very small mass
• Radioactivity is the spontaneous emission of radiation from unstable atoms
• Alpha particle is a helium ion with a mass of four protons and no electrons, it has a charge of +2
• Gamma ray is high energy electromagnetic radiation with no charge and no rest mass
• An alpha particle is very ionising and cannot leave your body. It is stopped by tissue paper
• Beta is stopped by aluminium and is somewhat ionising and penetrative
• Gamma is the least ionising but most penetrating and stopped by lead
• The half life of an element is the time taken for one half of its nuclei to decay into another form of matter.
• A radioisotope is an atom that decays over time due to instability within its nucleus
• Contamination is the presence of a radioactive substance in the mody or in the surface
• Irradiation is being exposed to radiation from an external source
• A radiation dose is a measure of the possible harm done to your body, which takes into account both the amount and type of radiation you are exposed to
• Background radiation is low-level radiation, mostly from natural sources, that everyone is exposed to all the time, everywhere