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    Fm

    Fermium

    Actinide

    Atomic Number: 100 • Atomic Mass: 257.0000 u • Period: 7 • Group: 102

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹²
    Phase: Solid
    Electronegativity: 1.3
    Einsteinium (Es)Mendelevium (Md)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    History

    Fermium has been known since ancient times

    Historical Timeline

    Discovered in debris from the first hydrogen bomb test