Scientists Contribution to Atomic Theory

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  • 492 BCE

    Democritus Contribution

    Democritus Contribution
    He observed that atoms have always been and will be in motion.

  • Dalton Contribution

    Dalton Contribution
    He observed that all atoms of an element were identical different elements had atoms of differing size and mass.

  • Thomson Contribution

    Thomson Contribution
    He discovered the electron and created the Plum Pudding Model.

  • Rutherford Contributions

    Rutherford Contributions
    He created the Rutherford model which shows the nucleus of an atom containing protons and neutrons being orbited by shells of electrons.

  • Bohr Contributions

    Bohr Contributions
    Observed that their is a small positively charged nucleus surrounded by orbiting electrons.

  • Millikan Contributions

    Millikan Contributions
    Measured the elementary electronic charge.

  • Chadwicks Contributions

    Chadwicks Contributions
    He discovered neutrons in atoms. He showed that neutrons do not have a positive charge nor a negative charge. Though they contribute the atomic weight with the same effect as a proton.