History of the Atom

By hlizzotte
  • 400 BCE

    Democritus

    In the year 400 B.C. Democritus came up with the Atomic Hypothesis. He believed that everything was made up of atoms that could never be destroyed.
  • 330 BCE

    Aristotle

    In 330 B.C. Aristotle believed that all things were made up of not atoms, but the the four elements of fire, earth, water, and air.
  • 1492

    Columbus Arrives in America

  • Robert Boyle

    Boyle disagreed with the notion the all things were made up of four basic elements fire, earth, water, and air and instead proposed that elements were a substance that could not be separated into similar components.

  • American Revolution

  • John Dalton

    Dalton is most known for his atomic theory in chemistry. The main points of Dalton's atomic theory are as follows;
    Elements are made of tiny particles called atoms,
    Atoms of a certain element are the exact same,
    Atoms cannot be subdivided, created or destroyed,
    Atoms of different elements combine to form chemical compounds,
    In chemical reactions, atoms are combined, separated or rearranged.

  • American Civil War

  • Dmitri Mendeleev

    Mendeleev is most know for his creation of the periodic table in which he organized all of the elements by their atomic weight

  • J.J. Thompson

    Thompson discovered the electron and the charge to mass ratio of the electron. He discovered this when experimenting with cathode ray tubes.

  • Hans Geiger

    Geiger, Marsden, and Rutherford carry out the gold foil experiment and discovered that there was a very small nucleus in the center of the atom.

  • Robert Millikan

    In 1908 Millikan started working on an experiment called the oil drop experiment. In this experiment he measured the charge of a single atom.

  • Ernest Rutherford

    In 1911, Rutherford came up with the Rutherford Model of the Atom, he made this after doing the gold foil experiment in 1909 to see that there was a very small nucleus in the center of the atom.

  • Neils Bohr

    In 1913 Neils Bohr came up with the Bohr Model of the Atom

  • World War 1

  • James Chadwick

    He proved that a neutron was a fundamental particle of the atom and not a proton-electron pair.

  • World War 2

  • Hiroshima

  • Present