Atomic Timeline

By rmurrayy24764
  • 403 BCE

    World event within 10 years of Democritus’ discovery

    World Event: Establishment of Athenian democracy around 403 BCE.
  • 400 BCE

    Democritus

    Democritus proposed that matter is made of indivisible atoms, laying the foundation for atomic theory. This idea influenced later scientists like Dalton.
  • John Dalton 'Marble Model"

    John Dalton 'Marble Model"

    John Dalton's atomic theory established that atoms are indivisible and that different elements have different types of atoms. This revived and formalized the concept of atoms in modern science.

  • World Event within 10 years of Dalton’s discovery

    World Event: The Napoleonic Wars began in 1803.

  • Michael Faraday

    Michael Faraday's discovery of electromagnetic induction showed the relationship between electricity and magnetism, influencing later atomic theories about electricity in atoms.

  • Eugen Goldstein

    Eugen Goldstein discovered canal rays, which revealed the existence of positively charged particles and led to a better understanding of atomic structure.
  • JJ Thomson “Plum Pudding” model

    JJ Thomson “Plum Pudding” model

    J.J. Thomson discovered the electron, demonstrating that atoms contain smaller charged particles. This altered the model of the atom from indivisible to having a subatomic structure.

  • World Event within 10 years of Thomson’s discovery

    World Event: The Spanish-American War occurred in 1898.
  • Ernest Rutherford “Nuclear” model

    Ernest Rutherford “Nuclear” model

    Ernest Rutherford discovered the nucleus through his gold foil experiment, leading to the realization that atoms have a dense center, changing the atomic model significantly.

  • Robert Millikan

    Robert Millikan measured the charge of the electron through his oil drop experiment, providing a precise value and confirming the existence of a quantized electric charge.
  • Niels Bohr “Solar System” model

    Niels Bohr “Solar System” model

    Niels Bohr introduced the Bohr model of the atom, which proposed that electrons orbit the nucleus in fixed paths, incorporating quantum theory into atomic structure.

  • World Event within 10 years of Bohr’s discovery

    World Event: World War I ended in 1918.
  • Edwin Schrödinger “Electron Cloud” model

    Edwin Schrödinger “Electron Cloud” model

    Erwin Schrödinger developed wave mechanics and the Schrödinger equation, introducing the concept of wave functions to describe electron behavior in atoms.

  • Werner Heisenberg

    Werner Heisenberg formulated the Uncertainty Principle, stating that certain pairs of physical properties cannot be simultaneously measured precisely, influencing quantum mechanics.

  • World Event within 10 years of Schrödinger's discovery

    World Event: The Great Depression began in 1929.
  • James Chadwick “Electron Cloud” model with neutrons added

    James Chadwick “Electron Cloud” model with neutrons added

    James Chadwick discovered the neutron in 1932, revealing that atoms have neutral particles in the nucleus, which refined the understanding of atomic structure.

  • World Event within 10 years of Chadwick’s discovery

    World Event: The rise of Adolf Hitler as Chancellor of Germany in 1933.