Americium (symbol Am, atomic number 95) is a synthetic actinide used in household smoke detectors. It is classified as a actinide and sits in the actinide series (f-block), period 7 of the periodic table.
Overview
Americium is the chemical element with atomic number 95 and the symbol Am. With a standard atomic weight of [243], it is a actinide. In the periodic table it occupies the actinide series (f-block) and period 7, and under standard conditions it is normally a solid. Americium is a synthetic actinide used in household smoke detectors.
Atomic structure
An atom of Americium has 95 protons in its nucleus and, when neutral, 95 electrons arranged in the configuration [Rn] 5f7 7s2. Americium has no stable isotope; the value [243] refers to the mass number of its most stable or most commonly produced isotope.
Discovery and place in the table
Americium was discovered in 1944 by Glenn T. Seaborg et al.. It follows Plutonium (Pu) and precedes Curium (Cm) in order of atomic number.
| Atomic number | 95 |
|---|---|
| Symbol | Am |
| Atomic mass | [243] |
| Category | Actinide |
| Group | — |
| Period | 7 |
| Electron configuration | [Rn] 5f7 7s2 |
| Phase at STP | Solid |
| Discovered | 1944 (Glenn T. Seaborg et al.) |