Atomic Timeline

By freyaolson
  • 430 BCE

    Democritus

    Democritus introduced the idea of the atom (that everything is made up of much smaller particles)
  • 430 BCE

    Plague in Athens

  • Louisiana Purchase

    Thomas Jefferson engineers the Louisiana Purchase.

  • John Dalton

    John Dalton
    John Dalton (1766-1844) proposed a theory that suggested that all matter is composed of solid atoms with different masses and properties.

  • Michael Faraday

    Michael Faraday (1971-1867) discovered electromagnetic induction using an induction ring.

  • Eugen Goldstein

    Eugen Goldstein (1850-1930) discovered canal rays- positively charged ions that are accelerated towards a perforated cathode.

  • JJ Thomson

    JJ Thomson
    JJ Thomson (1856-1940) discovered the electron and proposed a new model of the structure of an atom called the plum pudding model. this model shows negatively charged particles floating in a positively charged “soup”.

  • Theodore Roosevelt becomes president

  • Robert Millikan

    Robert Millikan (1886-1953) discovered that electrons have a fixed, measurable charge and his work allowed scientists to be able to calculate the mass of an electron.

  • Ernest Rutherford

    Ernest Rutherford
    Ernest Rutherford (1871-1937) discovered alpha and beta rays and the nucleus of an atom. the discovery of the nucleus led hm to be able to make the nuclear model of the atom.

  • Neils Bohr

    Neils Bohr
    Neils Bohr (1885-1962) proposed a model of the atom where each electron could only occupy its specific orbit around the nucleus, which is called the solar system model.

  • Sinking of Titanic

  • Werner Heisenberg

    Werner Heisenburg (1901-1976) formulated quantum mechanics in terms of matrices and significantly contributed to atomic theory.

  • Edwin Schrödinger

    Edwin Schrödinger
    Edwin Schrödinger (1887-1961) formulated an equation that could calculate the energy levels of electrons and proposed the electron cloud model which shows a “cloud” of space around the nucleus where the electron(s) could be.

  • Great Depression started

  • James Chadwick

    James Chadwick
    James Chadwick (1891-1974) proved the existence of neutrons in the atom. Neutrons are subatomic particles that are found in the nucleus along with protons.