This article aims to introduce the actinides and some aspects of nuclear chemistry to teachers and their students. The actinides are a group of f-block elements with atomic numbers from 90 to 103. (The term 'actinoids' encompasses both the actinides and actinium itself). All of the actinides are radioactive but they also have a rich inorganic chemistry and a range of industrial uses in addition to nuclear power. Understanding actinide chemistry is critical for developing approaches for nuclear waste treatment as well as for establishing the role of f orbitals in bonding and reactivity. The transactinides (superheavy elements) are recently synthesised radioactive elements with atomic numbers greater than 103.