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Chemistry LibreTexts

2: Atoms and Elements

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  • Unit 2 Objectives 

    By the end of this unit, you will be able to: 

    • State the postulates of Dalton’s atomic theory
    • Use postulates of Dalton’s atomic theory to explain the laws of definite and multiple proportions
    • Outline milestones in the development of modern atomic theory
    • Summarize and interpret the results of the experiments of Thomson, Millikan, and Rutherford
    • Describe the three subatomic particles that compose atoms
    • Define isotopes and give examples for several elements
    • Write and interpret symbols that depict the atomic number, mass number, and charge of an atom or ion
    • Define the atomic mass unit and average atomic mass
    • Calculate average atomic mass and isotopic abundance


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