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A time line of atomic theory

By Kylah12

  • Dalton's atomic theory

    -took Democritus' idea about matter and revised them based off of his personal scientific research.
    Revised the term "atom"
    "Atoms are the smallest particles of matter and are invisible and indestructible."
    "Atoms can be rearranged, separated, or combined to form new things, but cannot be created, destroyed, or divided in the process."

  • J.J Thomas

    Designed a series of CRT experiments at Cambridge to determine the ratio of the particle's charge to its mass.
    The mass of the particles was much less than that of the Hydrogen atom, which disproved Dalton's theory that atoms were invisible.

  • James Chadwick (1891 – 1974)

    English physicist, James Chadwick (1891 – 1974) demonstrated that the nucleus had another neutral subatomic particle, the neutron
    Neutrons are subatomic particles that carry no electric charge and weighs just about the same as a proton.Chadwick won the 1935 Nobel prize for his discovery of the neutron.

  • Aristotle (384-322 B.C)

    Aristotle (384-322 B.C)
    -Disagreed with Democritus' idea that atoms move through Emory space. -completely denied the existence of atoms due to personal ideas about nature

  • Democritus (460-370 B.C)

    Democritus (460-370 B.C)
    First person to suggest that matter could not be infinitely divided.
    Coined the term "atoms" to describe the tiny particles that make up matter and that move through empty space.
    "Atoms"can not be created, destroyed, or further divided.

  • Robert Millikan

    Designed an oil drop apparatus to determine the charge of the electron
    Determined that the magnitude of the charge of the electron was 1.602x10

  • Rutherford

    Based on the results of his gold foil experiment, Rutherford came to the conclusion that Thomson’s plum pudding model of the atom was incorrect.
    Rutherford calculated that an atom was mostly just empty space
    Rutherford’s theory explained that the negatively-charged electrons were held within the atom by their attraction to the positively-charged nucleus.The nucleus must also be extremely dense, because it contains the majority of the mass of the atom in such a tiny volume within the atom.