Atomic Properties of Am
- Atomic Number of Am
- 95
- Atomic Mass of Am
- 243.0000 u
- Electron Configuration
- [Rn] 5f7 7s2
- Electronegativity
- 1.13
- Block
- f-block
- Group
- —
- Period
- 7
Glenn Seaborg, Ralph James, Leon Morgan, and Albert Ghiorso produced americium during wartime reactor work in 1944. The name honors the Americas and mirrors europium above it in the periodic table. Americium formed as plutonium absorbed neutrons and underwent beta decay, making its discovery a product of deliberate nuclear transformation.
The place most people never think about is an ionization smoke alarm. A very small sealed americium-241 source emits alpha particles that ionize air between electrodes, allowing a tiny current. Smoke entering the chamber disrupts that current and triggers the alarm. The source does not “sense” smoke intelligently, and the battery still powers the alarm electronics. Users should test alarms, replace them according to guidance, and follow local disposal rules rather than dismantling the source.
Americium-241 has a half-life of about 432 years. Americium-243 lasts much longer, around 7,370 years. Both are radioactive; external alpha radiation is easily blocked, but americium inside the body presents a serious contamination hazard. Engineered encapsulation is what makes the household application manageable.
In laboratories, americium serves as a stepping stone to heavier actinides and as a source for spectroscopy and nuclear measurements. Its compounds also reveal changing actinide oxidation chemistry.
This Corebound watcher succeeds by being small, sealed, and specific. A controlled alpha source maintains an electrical baseline; airborne particles disturb it. Everyday protection emerges from nuclear decay, circuit design, regulation, and maintenance working as one system.