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    Md

    Mendelevium

    Actinide

    Atomic Number: 101 • Atomic Mass: 258.0000 u • Period: 7 • Group: 102

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹³
    Phase: Solid
    Electronegativity: 1.3
    Fermium (Fm)Nobelium (No)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    Physical & Chemical Properties

    Physical Properties

    • •Presumed to be metallic and silvery
    • •Highly radioactive
    • •Too short-lived to observe bulk properties
    Melting Point

    1100 K (826.85 °C, 1520.33 °F)

    Boiling Point

    1373 K (1099.85 °C, 2011.73 °F)

    Density

    10.3 g/cm³

    Electronegativity

    1.3 (Pauling scale)

    Chemical Properties

    • •Forms +2 and +3 oxidation states
    • •Unusual +2 state is more stable than in other actinides
    • •Similar to thulium chemically

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹³

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