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    Ac

    Actinium

    Actinide

    Atomic Number: 89 • Atomic Mass: 227.0000 u • Period: 7 • Group: 3

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹⁴ 5d¹⁰ 6p⁶ 7s² 6d¹
    Phase: Solid
    Electronegativity: 1.1
    Radium (Ra)Thorium (Th)
    OverviewPropertiesAtomic StructureOccurrenceApplicationsHistory

    Overview

    Actinium is the chemical element with the symbol Ac and atomic number 89. 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:Ac
    • Atomic Number:89
    • Atomic Mass:227.0000 u
    • Group:3
    • Period:7
    • Category:Actinide
    • Phase at STP:Solid
    • Electronegativity:1.1 (Pauling scale)

    Key Facts

    Fun Fact #1

    Name means 'ray' in Greek

    Fun Fact #2

    First actinide element

    Common Uses

    • Neutron source
    • Thermoelectric generators
    • Research