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    La

    Lanthanum

    Lanthanide

    Atomic Number: 57 • Atomic Mass: 138.9100 u • Period: 6 • Group: 3

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 5d¹
    Phase: Solid
    Electronegativity: 1.1
    Barium (Ba)Cerium (Ce)
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    Physical & Chemical Properties

    Physical Properties

    • •Silvery-white metal
    • •Malleable and ductile
    • •Reactive with air and water
    Melting Point

    1193 K (919.85 °C, 1687.73 °F)

    Boiling Point

    3737 K (3463.85 °C, 6266.93 °F)

    Density

    6.145 g/cm³

    Electronegativity

    1.1 (Pauling scale)

    Chemical Properties

    • •Oxidizes in air
    • •Reacts with hot water
    • •Forms trivalent compounds

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 5d¹

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