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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)
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    Physical & Chemical Properties

    Physical Properties

    • •Presumed to be metallic and silvery
    • •Highly radioactive
    • •Never observed in bulk quantities
    Melting Point

    1800 K (1526.85 °C, 2780.33 °F)

    Boiling Point

    1800 K (1526.85 °C, 2780.33 °F)

    Density

    9.7 g/cm³

    Electronegativity

    1.3 (Pauling scale)

    Chemical Properties

    • •Forms primarily +3 oxidation state
    • •Similar to erbium in chemical properties
    • •Limited chemical studies due to short half-life

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹²

    Electron configuration describes how electrons are distributed in atomic orbitals, showing how they are arranged in energy levels and subshells.