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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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    Occurrence

    Protactinium is found in various natural sources, including minerals, rocks, and the Earth's crust.

    • Extremely rare in nature
    • Found in trace amounts in uranium ores
    • About 0.1 parts per trillion in Earth's crust