Ca
Calcium is the most abundant metal in the human body, essential for bones, teeth, and cellular signaling.
Physical Properties
| Atomic Mass | 40.078 u |
| Density | 1.55 g/cm³ |
| Melting Point | 1115.0 K |
| Boiling Point | 1757.0 K |
| Appearance | Dull gray, silver metallic |
| State at Room Temp | Solid |
Chemical Properties
| Electronegativity | 1.0 (Pauling) |
| 1st Ionization Energy | 589.8 kJ/mol |
| Electron Affinity | 2.37 kJ/mol |
| Oxidation States | +1, +2 |
Atomic Properties
| Electron Configuration | [Ar] 4s2 |
| Atomic Radius | 197.0 pm |
| Covalent Radius | 176.0 pm |
| Van der Waals Radius | 231.0 pm |
Discovery
| Discovered By | Humphry Davy |
| Discovery Year | 1808 |
| Location | London, England |
| Named After | Latin 'calx' meaning lime |
About Calcium
Calcium is a soft, silvery-white alkaline earth metal and the fifth most abundant element in Earth's crust. It is essential for bones, teeth, and shells. Calcium ions serve as key signaling molecules in cellular processes.
Uses & Applications
Cement and concrete, plaster of Paris, steel refining, antacids, dietary supplements, and water treatment.
Fun Fact
The human body contains about 1 kg of calcium, 99% in bones and teeth. Your skeleton is replaced about every 10 years.
Isotopes
| Mass Number | Abundance | Half-Life | Stable |
| 40 | 0.96941% | - | Yes |
| 42 | 0.00647% | - | Yes |
| 44 | 0.02086% | - | Yes |
Electron Configuration
[Ar] 4s2