Actinium is used as a source of neutrons. Thorium is used in the glowing mantles in gas lanterns. Protactinium is very rare and has few uses. It is used in nuclear power plants and nuclear weapons. Neptunium is used in neutron detectors.
Plutonium is used in nuclear power plants and nuclear weapons.
Americium is used in smoke detectors. Curium is used as a power source in spacecraft. Berkelium has few uses. Californium is used in instruments such as moisture gauges. As of 1997, element 112 was the highest-numbered element yet created.