Actinides are a group of elements that reside in the bottom row of the periodic table. These elements have a lot of similarities in terms of their chemical properties, and they are often referred to as the actinide series. Some alternate terms for these elements include actinoids, actinium series elements, or simply actinide elements. Some other synonyms that are used to describe this group include the transuranic elements, heavy metals, and rare earth elements. This group of elements includes some of the most unstable and radioactive elements known to science, such as uranium, plutonium, and curium. Actinides are widely used in nuclear energy and weaponry, making them of great importance in modern science and society.