Atom with electrons

The History of Atomic Theory

  • Period: 300 to

    History of the Atomic Theory

  • 350


    Aristotle invented the scientific method, this helped scientists of the future in organizing their labs. But Aristotle didn't help in discovering the atom, instead he rgued against and created a new more largly excepted theory.
  • 350

    The theatre at Epidavros is built

     The theatre at Epidavros is built
    the theatre at Epidavros
  • 400


    Democritus made the most imporatnt step in the history of the atom. He decided that everything was made up of tiny things called atoms, this idea lead to everyting after. He also created the first atomice model the exclude electrons, neutrons, protons, and a nucleus.
  • Smallpox Vaccination

     Smallpox Vaccination
    Edward Jenner's smallpox vaccination is introduced
  • Joseph Proust

    Joseph Proust
    Proust proposed the Law of Definite Proportions. This law states that the proportion of the masses of two elements will always stay the same. He also said theat all element compunds have unique characteristics.
  • No Slaves

    No Slaves
    Congress prohibits importation of slaves
  • John Dalton

    John Dalton
    Dalton suggested the atomic theory which stated that "(1) all matter was composed of small indivisible particles termed atoms, (2) atoms of a given element possess unique characteristics and weight, and (3) three types of atoms exist: simple (elements), compound (simple molecules), and complex (complex molecules)."This idea laid down all ground work for future scientist in creating models and discoveing the atom at a deeper level.
  • Railroad in Hawii

    Railroad in Hawii
    1st railroad opens in Hawaii
  • Max Planck

    Max Planck
    Planck had the idea for the Quantom Theory, this theory was the later used by scientists across the globe. Planck also did extensive research on Thermodynamics, atoms make energy by rgainging electrons. Planck is also famous for his the consatnt he created named Planck's constant, this the size of a quanta in quantum mechanics.
  • 1st modern Olympic Games

    1st modern Olympic Games
    1st modern Olympic Games officially opens in Athens
  • Henri Becquerel

    Henri Becquerel
    Becquerel discover spontaneous radioactivity useing Uranium salts. Spontaneus radioactivity is the disigration of an atoms nucleus, radioactive rays are the released.
  • J.J. Thomson

    J.J. Thomson
    Thomson dicovered electrons, this is a big deal concerning atoms. Electrons souround the nucleus and determine how excited the atom is. the atmic number is also the number of electrons so, this discovery had an effect on the Periodic Table also. Thomson also created one of the first atomic models; it was called the lpum pudding model.
  • Fire in Paris

    Fire in Paris
    Fire in Paris bazaar at Rue Jean Goujon kills 200
  • 1st British bus service opens

    1st British bus service opens
    1st British bus service opens
  • Ernest Rutherford

    Ernest Rutherford
    Rutherford discovered a new noble gas, radon, and he created a new model of the atom. This model included a nucleus and electrons. Also he was the first to transform in element to another on purpose.
  • Robert Milikan

    Robert Milikan
    Milikan determind that an electrical chrage came from electrons and the the amount of energy released from each is a constant for all atoms. After this conclusion was made Milikan confimed Plancks constant.
  • England's 1st aircraft flight

    England's 1st aircraft flight
    England's 1st aircraft flight
  • 10 Day Tragedy

    10 Day Tragedy
    10 Day Tragedy of Mexico-City; 3,000 die
  • Niels Bohr

    Niels Bohr
    Bohr created another version of the atomic model. This model had shelves surounding the nucleus and each shelf could hold a certain amount of electrons. This model, tjough not completely accurate, is still used today to teach the basics of electron configuartions.
  • Werner Heisenberg

    Werner Heisenberg
    Heisenberg formed new ideas concerning quantum mehanics. Quantum mechanics describes the way atoms move. This helped scientist see how atoms act in their own elements and on the larger scale.
  • Klu Klux Klan

    Klu Klux Klan
    1st national march of Ku Klux Klan (200,000) in Washington, D.C.
  • Erwin Schrodinger

    Erwin Schrodinger
    Schrodinger worked with thermodynamics and the atomic spectra. He also tried to proove Bohrs model wrong and created alot of contriversy.
  • World Court

    World Court
    U.S. Senate agrees to join World Court
  • Louis de Broglie

    Louis de Broglie
    Broglie discovered the wave nature of electrons and electron diffraction by crystals. These both describe the movment of electrons and therefore are important to the atom because electrons are in the atom.
  • James Chadwick

    James Chadwick
    Chadwick proved that protons exsisted, this changed the early atomic models. He was then able to start to disinigrate the nucleus of atoms and began the journey to the atomic bomb.
  • Mahatma Gandhi

    Mahatma Gandhi
    Britian impriosions Ghandi.
  • Firts Catapult

    Firts Catapult
    the catapult is invented in Syracuse by Dionysius the Elder