Calcium (Ca) - Element 20 | Properties & Electron Configuration
What is Calcium?
Calcium (Ca) is element 20, a alkaline earth metal in period 4, group 2. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s².
| Atomic Number | 20 |
| Symbol | Ca |
| Atomic Mass | 40.078 u |
| Category | Alkaline Earth Metal |
| Period | 4 |
| Group | 2 |
| Block | s |
| Electron Configuration | 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² |
| Short Config | [Ar] 4s² |
| Electronegativity | 1 |
| Atomic Radius | 180 pm |
| Ionization Energy | 590 kJ/mol |
| Electron Affinity | 2 kJ/mol |
| Phase (STP) | Solid |
Electron Configuration
The full electron configuration of Calcium is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s². In noble gas shorthand, this is written as [Ar] 4s².
Calcium is a s-block element in group 2, period 4.
Periodic Trends
Electronegativity: Calcium has a Pauling electronegativity of 1. Within group 2, electronegativity generally decreases down the group.
Atomic Radius: 180 pm. Across period 4, atomic radius generally decreases left to right as nuclear charge increases.
Ionization Energy: 590 kJ/mol. Ionization energy generally increases across a period and decreases down a group.
View all 118 elements with trend overlays for electronegativity, atomic radius, ionization energy, and electron affinity.
Explore Calcium on the Interactive Periodic TableRelated Topics
Beryllium (Be)
Properties of Beryllium - same group as Calcium
Magnesium (Mg)
Properties of Magnesium - same group as Calcium
Strontium (Sr)
Properties of Strontium - same group as Calcium
Potassium (K)
Properties of Potassium - same period as Calcium
Scandium (Sc)
Properties of Scandium - same period as Calcium
Titanium (Ti)
Properties of Titanium - same period as Calcium