Atomic Theory

By Lexy Skelly
  • 460 BCE

    Democritus

    Democritus
    Full Name: Democritus
    Birth: 460 BC
    Death: 370 BC
    Year of Discovery: 460-370 BC
    Experiment/Theory: Stated that the universe was made up of 2 elements: the void, as well as atoms. He explained that atoms are small quantities of matter.
    Fact: He was born in a place called Abdera.
  • Period: 460 BCE to

    Atomic Theory

  • Dalton

    Dalton
    Full Name: John Dalton
    Birth: 1766
    Death: 1844
    Year of Discovery: 1803
    Experiment/Theory: Theorized that all things are composed of atoms, atoms cannot be split, all atoms of the same element are alike, and different elements are composed of different atoms.
    Fun Fact: He taught at a school at the young age of 12.

  • Thomson

    Thomson
    Full Name: Joseph John Thompson
    Birth: 1856
    Death: 1940
    Year of Discovery: 1897
    Experiment/Theory: Proposed the idea of negatively charged electrons as well as positive charges. Thought atom was full of positive charge, but negative electrons were distributed evenly with the positive charge. Said if atom had more positive mass, it'd be positively charged. Vice versa.
    Fun Fact: He is buried close to the grave of Sir Isaac Newton.

  • Millikan

    Millikan
    Full Name: Robert Millikan
    Birth: 1868
    Death: 1953
    Year of Discovery: 1910
    Experiment/Theory: Discovered there is an electric charge to the charge of an electron. He did the oil-drop experiment which involved two electrostatic oil drops being balanced and caused to halt mid-air due to gravitational forces.
    Fun Fact: Millikan enjoyed tennis thoroughly.

  • Rutherford

    Rutherford
    Full Name: Ernest Rutherford
    Birth: 1871
    Death: 1937
    Year of Discovery: 1911
    Experiment/Theory: Experimented with gold foil. A beam of particles was pointed towards gold foil, with a majority passing through. From this information, it was concluded that most of the atom is empty space in the surrounding of the nucleus. He stated that electrons orbit the nucleus but met his demise before he could prove it.
    Fun Fact: Rutherford was the first person from Oceania to win a Nobel prize.

  • Bohr

    Bohr
    Full Name: Niels Bohr
    Birth: 1885
    Death: 1962
    Year of Discovery: 1913
    Experiment/Theory: Experimented with nuclear fission. Theorized that there is a predetermined route in the orbit of electrons.
    Fun Fact: Bohr's experiments with nuclear fission later led to the creation of the atomic bomb.

  • Heisenberg

    Heisenberg
    Full Name: Werner Heisenberg
    Birth: 1901
    Death: 1976
    Year of Discovery: 1926
    Experiment/Theory: Heisenberg discovered that a force holds an atom together and subatomic particles are drawn to the nucleus. He also continued Bohr's experiment by doing equations to figure out the probability of finding an electron in a precise location.
    Fun Fact: He played complex compositions on the piano at a very young age.

  • Schrodinger

    Schrodinger
    Full Name: Erwin Rudolf Josef Alexander Schrodinger
    Birth: 1887
    Death: 1961
    Year of Discovery: 1926
    Experiment/Theory: Solved equations to figure out the probability of an electron being found at a precise location.
    Fun Fact: Schrodinger had an experiment regarding trying to distinguish whether a cat was alive or not when stuffed in a box and left unopened for some time.

  • Chadwick

    Chadwick
    Full Name: James Chadwick
    Birth: 1891
    Death: 1974
    Year of Discovery: 1932
    Experiment/Theory: Discovered the neutron by bombarding the beryllium atom with alpha particles. In the process of that, an unknown radiation was produced that is now known as the neutron.
    Fun Fact: He was held in a German prison camp for all of WWI.