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    Cl

    Chlorine

    Halogen

    Atomic Number: 17 • Atomic Mass: 35.4500 u • Period: 3 • Group: 17

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁵
    Phase: Gas
    Electronegativity: 3.16
    Sulfur (S)Argon (Ar)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    History

    Chlorine has been known since ancient times

    Historical Timeline

    Discovered by Carl Wilhelm Scheele in 1774

    First identified as an element by Humphry Davy in 1810

    Named by Humphry Davy based on its color

    First used as chemical weapon in World War I