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Atomic History Timeline

  • 330

    Aristotle 384/322 BCE

    Aristotle 384/322 BCE
    Considered the father of biology
  • 460

    Democritus

    Democritus
    -he came up with the idea of the atom and he called it the falling atom.
  • Joseph Louis Proust

    Joseph Louis Proust
    Formulated his law of definite proportions. Generalized that all compounds contain elements in certain definite proportions.
  • John Dalton

    John Dalton
    -He proposed the Atomic Theory in 1803 which stated that all matter was composed of small indivisible particles termed atoms, atoms of a given element possess unique characteristics and weight, and there are three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules).
  • Michael Faraday

    Michael Faraday
    Discovered electromagnetic induction with atoms.
  • Henri Becquerel

    Henri Becquerel
    In 1896 Henri Becquerel discovered the phenomenon of natural radioactivity. He then used his discovery of natural radioactivity and did an expierament using uranium salts.placed near the photographic plate covered with opaque paper, and it then fogged. This was concluded to be a property of the uranium atom.
  • J.J. Thomson

    J.J. Thomson
    -an original study of cathode rays culminating in the discovery of the electron.
    -he also stated that the atom looks like plum pudding, he invented the plum pudding model.
  • Max Planck

    Max Planck
    The energy for the resonator of frequency v is hv is a universal constant, now called planck's constant.
  • Peirre Curie

    Peirre Curie
    -He was the husband of marie curie, assistes her in the discovery of the radioactive metals.
    -Peirre and Marie found that the harmful properties of x-rays were able to kill tumors.
  • Marie Curie

    Marie Curie
    -Marie Curie was the founder of radioactive metals, examples are Radium and Polonium.
    -She was honored in 1901.
  • Robert Millikan

    Robert Millikan
    His earliest major success was accurate determination of the charge carried by an electron. He demonstated the atomic structure of electricity.
  • Niels Bohr

    Niels Bohr
    Niels Bohr explained how atoms, with electrons orbiting a central nucleus, ahchieve stability by assuming that their angular momentum is quantized.
  • Albert Einstein

    Albert Einstein
    Einstein dealt with classical problems of statistical mechanics and problems, these were then merged with the quantum threory. This led to the explanation of the browian movement of molecules.
  • Antoine Lavoiser

    Antoine Lavoiser
    -He came up with the phlogiston theory which involved a weightless or nearly weightless substance known as phlogiston.
  • James Chadwick

    James Chadwick
    -Chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons.
  • Ernest Rutherford

    Ernest Rutherford
    -Assisted in helping chadwick made a fundamental discovery in the domain of nuclear science: he proved the existence of neutrons.
    -Came up with the model of the electron cloud model