Calcium (Ca)
Calcium (Ca, element 20) is an alkaline earth metal in group 2, period 4. Atomic mass 40.078, electron configuration [Ar] 4s², uses and facts.
About Calcium
Calcium is an alkaline earth metal with the symbol Ca and atomic number 20. It is a solid at room temperature, and it sits in group 2, period 4 of the periodic table. Calcium was discovered in 1808 by Humphry Davy.
Calcium key facts
- Atomic number: 20
- Symbol: Ca
- Atomic mass: 40.078 u
- Category: alkaline earth metal
- Group: 2
- Period: 4
- State at room temperature: solid
- Electron configuration: [Ar] 4s²
- Electronegativity (Pauling): 1
- Melting point: 1115 K (841.85 °C)
- Boiling point: 1757 K (1483.85 °C)
- Density: 1.55 g/cm³
- Common oxidation states: +2
Electron configuration
The electron configuration of calcium is [Ar] 4s². The part in brackets is the noble gas core; the rest shows how the outer electrons fill their subshells. Calcium has 2 valence electrons.
Uses of calcium
- Bones & teeth
- Cement
- Antacids
Did you know?
Human bones are ~70% calcium phosphate. You literally have calcium architecture holding you up.
Other elements in group 2 and neighbours
Frequently asked questions
What is the atomic number of calcium?
The atomic number of calcium is 20, which means every calcium atom has 20 protons.
What is the electron configuration of calcium?
The electron configuration of calcium is [Ar] 4s².
What group and period is calcium in?
Calcium is an alkaline earth metal in group 2, period 4.
What state is calcium at room temperature?
Calcium is a solid at room temperature.
What is calcium used for?
Calcium is used for bones & teeth, cement, antacids.