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CalciumCa Electron 1 Electron 2 Electron 1 Electron 2 Electron 3 Electron 4 Electron 5 Electron 6 Electron 7 Electron 8 Electron 1 Electron 2 Electron 3 Electron 4 Electron 5 Electron 6 Electron 7 Electron 8 Electron 1 Electron 2

Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.

20 Atomic Number
40.08 Atomic Mass (u)
1112.15 Melting Point (K)
1757 Boiling Point (K)
1.55 Density (solid: g/cm³, gas: g/liter)
2.2 Atomic Radius (Å)
1.76 Covalent Radius (Å)
1 Electronegativity
6.11 First Ionization Energy (eV)
2.37 Electron Affinity
4 Number of Shells
2 Electron Valency
2, 8, 8, 2 Electron Shell Occupations
0.65 Specific Heat (J/g)