|Atomic mass||(243) amu|
Americium, named after the Americas, was discovered in 1944. It can be produced from intense neutrons irradiations of pure plutonium. The problems involved in the extraction of americium include the recovery of the expensive starting material and the removal of hazardous fission products that are formed simultaneously in amounts comparable to the amounts of the element itself.
Shown in the image to the right is its oxide in gram quantities.