Americium is a radioactive chemical element with the symbol Am and the atomic number 95. In chemistry, it is placed in a group of metal elements named the actinides. Americium is a transuranic element (Transuranic means after uranium as all the elements used after uranium are man-made). Americium does not exist in nature and has to be made by people. It has a silver color. Americium is made by bombarding a plutonium target with neutrons.
It was the fourth transuranic element to be discovered. It was named for America, like Francium was named for France.[1][2]
The longest half life of any type of americium is 7370 years.[3]