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Element 20 - Calcium (Ca) sound

From calx. or lime--an oxide of calcium; discovered 1808; fifth most abundant in the earth's crust. Its presence in our bodies is essential. Normal quota in an adult is about two pounds, mostly in the teeth and bones. Calcium also plays a role in regulating the heartbeat.

Properties

Atomic Number: 20
Atomic Weight: 40.078
Electron Configuration (at ground state): 1s22s22p63s23p64s2
Oxidation States (Bold most stable): +2
Boiling Point (K): 1757
Melting Point (K): 1112
Density (at 300K -- g/cm3): 1.55
Atomic Volume (at 300K -- cm3/mol) 29.90
Number of stable isotopes: 6
Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: 45 -- 165 days -- beta particle (electron) emission
Covalent Radius (Å): 1.74
Atomic Radius (Å): 1.97
First Ionization Potential (V): 6.113
Electronegativity (Pauling's): 1.00
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.647
Heat of Vaporization (kJ/mol): 154.67
Heat of Fusion (kJ/mol): 8.53
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 31.3
Thermal Conductivity (at 300K -- W m-1 K-1): 200
Crystal Structure: Cubic, face centered
Acid-Base Properties: Very basic