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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)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    Overview

    Protactinium is the chemical element with the symbol Pa and atomic number 91. It belongs to the Actinide group and is located in period 7 of the periodic table. It exists as a solid under standard conditions.

    Basic Information

    • Symbol:Pa
    • Atomic Number:91
    • Atomic Mass:231.0400 u
    • Group:102
    • Period:7
    • Category:Actinide
    • Phase at STP:Solid
    • Electronegativity:1.5 (Pauling scale)

    Key Facts

    Fun Fact #1

    Name means 'parent of actinium'

    Fun Fact #2

    Extremely rare and toxic

    Common Uses

    • Scientific research
    • Nuclear reactions
    • Age determination of ancient objects