95Am[243]
Americium (Am)
Element 95 · Actinide
Americium (Am) is a chemical element with atomic number 95. It is classified as an actinide in period 7 of the periodic table (the f-block). Its most stable known isotope has mass number 243 and its ground-state electron configuration is [Rn] 5f⁷ 7s².
Americium facts
| Atomic number (Z) | 95 |
|---|---|
| Symbol | Am |
| Mass number of most stable isotope | [243] |
| Category | Actinide |
| Group | — (f-block) |
| Period | 7 |
| Block | f-block |
| Electron configuration | [Rn] 5f⁷ 7s² |
| Electronegativity (Pauling) | 1.3 |
| State at 20 °C | Solid |
| Protons / electrons | 95 / 95 |
| Neutrons (most common isotope, approx.) | 148 |
| Molar mass | 243 g/mol |