Properties

Atomic Number	95
CAS Registry Number	7440-35-9
Chemical Symbol	Am

History

The atomic number is 95 and the chemical symbol is Am. The name derives from America where it was first synthesized in a series of successive neutron capture reactions in the element plutonium 239Pu in a nuclear reactor in 1944 by American scientists under Glenn T. Seaborg at the University of California lab in Berkeley California using the nuclear reaction 239Pu (nγ) 240Pu (nγ) 241Pu -> β --> 241Am. Americium is the sixth element in the Actinide series of elements and is named in analogy to Europium which is the sixth element in the Lanthanide series of elements. The longest half-life associated with this unstable element is 7370 year 243Am.

Holden, Norman E., (2004). History of the origin of the chemical elements and their discoverers. National Nuclear Data Center. Retrieved from http://www.nndc.bnl.gov/content/elements.html