Back to Elements
    Kr

    Krypton

    Noble Gas

    Atomic Number: 36 • Atomic Mass: 83.7980 u • Period: 4 • Group: 18

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
    Phase: Gas
    Electronegativity: 3
    Bromine (Br)Rubidium (Rb)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    History

    Krypton has been known since ancient times

    Historical Timeline

    Discovered in residue left after evaporating nearly all components of liquid air

    Discovered shortly after neon, as part of Ramsay's systematic search for noble gases

    Name reflects its hidden nature and difficulty in detection