Atomic structure and radiation
Radioactive elements give out radiation, and there are three different types. They penetrate materials in different ways, and take different amounts of time to decay.
Atoms contain three sub-atomic particles called protons, neutrons and electrons. The protons and neutrons are found in the nucleus at the centre of the atom. The electrons are outside the nucleus.
Radioactive elements give out ionising radiation from their nuclei. This happens all the time, whatever is done to the substance. For example, radiation is still given out if the substance is cooled in a freezer or involved in a chemical reaction.
Radioactive elements are found naturally in…