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    Co

    Cobalt

    Transition Metal

    Atomic Number: 27 • Atomic Mass: 58.9330 u • Period: 4 • Group: 9

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷
    Phase: Solid
    Electronegativity: 1.88
    Iron (Fe)Nickel (Ni)
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    Physical & Chemical Properties

    Physical Properties

    • •Hard, lustrous, silver-gray metal
    • •Ferromagnetic and can be magnetized
    • •High melting point (1768 K or 1495°C)
    • •Good conductor of heat and electricity
    • •Slightly malleable and very ductile when heated
    Melting Point

    1768 K (1494.85 °C, 2722.73 °F)

    Boiling Point

    3200 K (2926.85 °C, 5300.33 °F)

    Density

    8.86 g/cm³

    Electronegativity

    1.88 (Pauling scale)

    Chemical Properties

    • •Main oxidation states are +2 and +3
    • •Relatively unreactive, resistant to oxidation in air
    • •More reactive at elevated temperatures
    • •Forms numerous colored complexes
    • •Essential trace element for living organisms

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d⁷

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