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    Pa

    Protactinium

    Actinide

    Atomic Number: 91 • Atomic Mass: 231.0400 u • Period: 7 • Group: 102

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f² 6d¹
    Phase: Solid
    Electronegativity: 1.5
    Thorium (Th)Uranium (U)
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    Physical & Chemical Properties

    Physical Properties

    • •Silvery-metallic appearance
    • •Dense heavy metal
    • •Highly radioactive
    Melting Point

    1841 K (1567.85 °C, 2854.13 °F)

    Boiling Point

    4300 K (4026.85 °C, 7280.33 °F)

    Density

    15.37 g/cm³

    Electronegativity

    1.5 (Pauling scale)

    Chemical Properties

    • •Forms complex compounds
    • •Multiple oxidation states (primarily +5)
    • •Reacts with oxygen and halogens

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f² 6d¹

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