History of atomic theory timeline

By danica
  • 460

    Democritus

    Democritus
    First proposed the existence of an ultimate particle. Used the word "atomos" to describe this particle.

  • Boyel

    Boyel
    Boyle’s law states that at constant temperature for a fixed mass, the absolute pressure and the volume of a gas are inversely proportional. The law can also be stated in a slightly different manner, that the product of absolute pressure and volume is always constant.

  • Lavoisier

    Lavoisier
    was the first person to make good use of the balance. He was an excellent experimenter. After a visit with Priestly in 1774, he began careful study of the burning process. He proposed the Combustion Theory which was based on sound mass measurements He named oxygen He also proposed the Law of Conversation of Mass which represents the beginning of modern chemistry To support his work, Lavoisier was associated with a tax-collecting firm and was married to the daughter of the one of the fir

  • JJ Thomson's expariment

    JJ Thomson's expariment
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  • Dalton

    Dalton
    This law led directly to the proposal of the Atomic Theory in 1803. He also developed the concept of the mole and proposed a system of symbols to represent atoms of different elements. Dalton recognized the existence of atoms of elements and that compounds formed from the union of these atoms. He therefore assumed that simplest ratios would be used in nature and came up with a

  • Nagoka

    Nagoka
    Physicists in 1900 had just begun to consider the structure of the atom. The recent discovery by J. J. Thomson of the negatively charged electron implied that a neutral atom must also contain an opposite positive charge

  • Bohr

    Bohr
    Niels Bohr managed to explain the spectrum of atomic hydrogen by an extension of Rutherford's description of the atom. In that model, the negatively charged electrons revolve about the positively charged atomic nucleus because of the attractive electrostatic force according to Coulomb's law.

  • Rutherford

    Rutherford
    Rutherfords experimentErnst Rutherford proposed the nuclear atom as Rutherford proposed that all of the positive charge and all of the mass of the atom occupied a small volume at the center of the atom and that most of the volume of the atom was empty space occupied by the electrons

  • Thomson

    Thomson
    thompson's experimentJ. J. Thomson identified the negatively charged electron in the cathode ray tube in 1897. He deduced that the electron was a component of all matter and calculated the charge to mass ratio for the electron.

  • Arostotile

    Arostotile
    The controbution Aristotle made to the Atomic theory was that He believed in the four elements of air, earth, water and fire. Aristotle felt that regardless of the number of times you cut a form of matter in half, you would always have a smaller piece of that matter.