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Calcium (Ca)
Atomic number: 20 · Category: alkaline earth metal · Group 2 · Period 4 · Phase: Solid
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.
Block: s
Molar heat: 25.929
CPK color:#3dff00
Electronic structure
Electron configuration: 1s2 2s2 2p6 3s2 3p6 4s2
Configuration (semantic): [Ar] 4s2
Shells: 2, 8, 8, 2
Electronegativity (Pauling): 1
Electron affinity: 2.37
Ionization energies: 589.8, 1145.4, 4912.4, 6491, 8153, 10496, 12270, 14206, 18191, 20385, 57110, 63410, 70110, 78890, 86310, 94000, 104900, 111711, 494850, 527762
Periodic position
Group: 2
Period: 4
xpos: 2
ypos: 4
Spectral/Bohr images
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3D Model