37Rb85.468
Rubidium (Rb)
Element 37 Ā· Alkali metal
Rubidium (Rb) is a chemical element with atomic number 37. It is classified as an alkali metal in period 5, group 1 of the periodic table (the s-block). Its standard atomic weight is 85.468 u and its ground-state electron configuration is [Kr] 5sĀ¹.
Rubidium facts
| Atomic number (Z) | 37 |
|---|---|
| Symbol | Rb |
| Standard atomic weight | 85.468 u |
| Category | Alkali metal |
| Group | 1 |
| Period | 5 |
| Block | s-block |
| Electron configuration | [Kr] 5sĀ¹ |
| Electronegativity (Pauling) | 0.82 |
| State at 20 Ā°C | Solid |
| Protons / electrons | 37 / 37 |
| Neutrons (most common isotope, approx.) | 48 |
| Molar mass | 85.468 g/mol |