Back to Elements
    Es

    Einsteinium

    Actinide

    Atomic Number: 99 • Atomic Mass: 252.0000 u • Period: 7 • Group: 102

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹¹
    Phase: Solid
    Electronegativity: 1.3
    Californium (Cf)Fermium (Fm)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    Physical & Chemical Properties

    Physical Properties

    • •Silvery appearance (presumed)
    • •Highly radioactive
    • •Sufficient quantities never obtained to see with naked eye
    Melting Point

    1133 K (859.85 °C, 1579.73 °F)

    Boiling Point

    1269 K (995.85 °C, 1824.53 °F)

    Density

    8.84 g/cm³

    Electronegativity

    1.3 (Pauling scale)

    Chemical Properties

    • •Forms Es³⁺ ions
    • •Similar to holmium in chemical behavior
    • •Limited chemical studies due to high radioactivity

    Electron Configuration

    1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 5f¹¹

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