20Ca40.078
Calcium (Ca)
Element 20 Ā· Alkaline earth metal
Calcium (Ca) is a chemical element with atomic number 20. It is classified as an alkaline earth metal in period 4, group 2 of the periodic table (the s-block). Its standard atomic weight is 40.078 u and its ground-state electron configuration is [Ar] 4sĀ².
Calcium facts
| Atomic number (Z) | 20 |
|---|---|
| Symbol | Ca |
| Standard atomic weight | 40.078 u |
| Category | Alkaline earth metal |
| Group | 2 |
| Period | 4 |
| Block | s-block |
| Electron configuration | [Ar] 4sĀ² |
| Electronegativity (Pauling) | 1.0 |
| State at 20 Ā°C | Solid |
| Protons / electrons | 20 / 20 |
| Neutrons (most common isotope, approx.) | 20 |
| Molar mass | 40.078 g/mol |