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    Ca

    Calcium

    Alkaline Earth

    Atomic Number: 20 • Atomic Mass: 40.0780 u • Period: 4 • Group: 2

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²
    Phase: Solid
    Electronegativity: 1
    Potassium (K)Scandium (Sc)
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    Occurrence

    Calcium is found in various natural sources, including minerals, rocks, and the Earth's crust.

    • Never found as a free element in nature due to its reactivity
    • Constitutes about 3.64% of Earth's crust
    • Major component of limestone, chalk, gypsum, and marble
    • Found in minerals like calcite (CaCO₃), dolomite, and fluorite
    • Present in all living organisms, particularly in bones and teeth