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    Er

    Erbium

    Lanthanide

    Atomic Number: 68 • Atomic Mass: 167.2600 u • Period: 6 • Group: 101

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹²
    Phase: Solid
    Electronegativity: 1.24
    Holmium (Ho)Thulium (Tm)
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    Physical & Chemical Properties

    Physical Properties

    • •Silvery-white metal
    • •Malleable
    • •Ferromagnetic at low temperatures
    Melting Point

    1802 K (1528.85 °C, 2783.93 °F)

    Boiling Point

    3141 K (2867.85 °C, 5194.13 °F)

    Density

    9.066 g/cm³

    Electronegativity

    1.24 (Pauling scale)

    Chemical Properties

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

    Electron Configuration

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

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