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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)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    History

    Calcium has been known since ancient times

    Historical Timeline

    Isolated by electrolysis of lime mixed with mercury oxide

    Calcium compounds like lime have been used since ancient times

    The element wasn't isolated until the early 19th century