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    Ar

    Argon

    Noble Gas

    Atomic Number: 18 • Atomic Mass: 39.9480 u • Period: 3 • Group: 18

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶
    Phase: Gas
    Electronegativity: 0
    Chlorine (Cl)Potassium (K)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    History

    Argon has been known since ancient times

    Historical Timeline

    Discovered by Lord Rayleigh and William Ramsay in 1894

    First noble gas discovered on Earth

    Identified through investigation of why atmospheric nitrogen was more dense than laboratory nitrogen

    Ramsay received the Nobel Prize partly for this discovery