88Ra[226]
Radium (Ra)
Element 88 Ā· Alkaline earth metal
Radium (Ra) is a chemical element with atomic number 88. It is classified as an alkaline earth metal in period 7, group 2 of the periodic table (the s-block). Its most stable known isotope has mass number 226 and its ground-state electron configuration is [Rn] 7sĀ².
Radium facts
| Atomic number (Z) | 88 |
|---|---|
| Symbol | Ra |
| Mass number of most stable isotope | [226] |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 7 |
| Block | s-block |
| Electron configuration | [Rn] 7sĀ² |
| Electronegativity (Pauling) | 0.9 |
| State at 20 Ā°C | Solid |
| Protons / electrons | 88 / 88 |
| Neutrons (most common isotope, approx.) | 138 |
| Molar mass | 226 g/mol |