Americium is a radioactive transuranic chemical element with symbol Am and atomic number 95. This member of the actinide series is located in the periodic table under the lanthanide element europium, and thus by analogy was named after the Americas. Americium was first produced in 1944 by the group of Glenn T.Seaborg from Berkeley, California, at the metallurgical laboratory of University of Chicago.
Three reasons Americium stands out
- 1
Commonly found in smoke detectors, emitting alpha particles.
- 2
Only about 2 micrograms — an almost invisibly tiny amount — is used in each household smoke detector.
- 3
It was the first element to be synthesised through purely civilian, non-weapons research rather than a military programme.
A synthetic element guarding the hallway
Americium-241 emits alpha particles that ionize air inside many smoke detectors. Smoke disrupts the tiny current, triggering the alarm. The element was created during wartime plutonium research, then named for the Americas by analogy with europium across the lanthanide row.