Americium (Am)
"The Smoke Detector, the unsung hero protecting every home from fire."
A memorable persona to anchor Am in your mind.
13.67
Grams per cm³
1176
Celsius (°C)
244
Radius (pm)
Daily Life Link
Americium is found as the tiny radioactive source inside a household smoke detector.
Discovery & History
Year Discovered
1944
Discovered By
Glenn Seaborg and colleagues
Origin of Name
"Americium is named for America where it was first made."
Technical Properties
Atomic Mass
[243] u
Standard State
solid
Boiling Point
2011°C
Electron Configuration
[Rn] 5f77s2
1st Ionization Energy
5.993 eV
Electron Affinity
N/A
Oxidation States
"Americium is a silvery-white, radioactive metal."
Did You Know?
A very small amount (about 0.29 micrograms) of americium-241 is used in nearly all common household smoke detectors. It works by ionizing the air between two electrodes.
It was synthesized by Glenn T. Seaborg's team at the University of California, Berkeley, and was humorously nicknamed 'pandemonium' before it received its official name.
It is named after the Americas, in analogy to the element europium which was named after Europe.
During the Cold War, the element's discovery was kept secret and was only revealed to the public on a children's radio show in 1945.