Symbol: Am
Atomic number: 95
Category: actinides
Group: n/a
Period: 7
Block: f
Atomic weight: (243) g/mol
Electrons per shell: 2, 8, 18, 32, 25, 8, 2
CAS number: 7440-35-9
Phase: solid
Density: 12 kg/dm3 (near room temperature)
Melting point: 1449 K (1176 °C, 2149 °F)
Boiling point: 2880 K (2607 °C, 4725 °F)
Crystal structure: hexagonal
Oxidation states: 3, 4, 5, 6
Electronegativity: 1.3 (Pauling scale)
Name's origin: America
Name's meaning: by analogy with europium which was named after Europe
Facts:
- has a silvery and white luster
- slowly tarnishes in dry air
- is more silvery than plutonium or neptunium and apparently more malleable than neptunium or uranium
- is unlikely that Americium would be used as a weapons material, as its minimum critical mass is considerably larger than that of more readily obtained plutonium or uranium isotopes
- is widely used in commercial ionization-chamber smoke detectors as well as in neutron sources and industrial gauges
- eighteen radioisotopes of americium have been characterized, with the most stable being americium-243 with a half-life of 7370 years
- americium-241 has recently been suggested for use as a denaturing agent in plutonium reactor fuel rods to render the fuel unusable for conversion to nuclear weapons