Davidsons Atomic Model

Timeline created by davidson14178
  • Jan 1, 1000


    Democritus believed that matter consisted of very small particles, which he called atoms, that can't be divided. He also thought that there were different types of atoms that haad specific properties.
  • Oct 28, 1000


    Aristotle did not believe that there was a limit to the number of times that matter could be divided. In order to do this, he experimented many times.
  • John Dalton

    John Dalton
    John Dalton gathered evidence for the existence of atoms. He did thisby measuring masses of elements that combine when compounds are formed. Also, heconcluded that a gas conisists of individual particles. John Dalton said that all matter is made up of individual particles called atoms.
  • J.J Thomson

    J.J Thomson
    J.J Thomson hypothesized that a sealed glowing beam with gas at low pressure was a stream of charged partriclesthat interact with the air in the tube which caused the air to glow. He used an electric current to learn more about atoms. His experiments provided the first evidence that atoms are made of smaller particles.
  • Hantaro Nagaoka

    Hantaro Nagaoka
    Nagaoka believed that an atom has a central nucleus and that they move in orbits like the rings around saturn.
  • Rutherford

    Rutherford discoverd that uranium releases fast-moving particles that have a positive charge. In order to prove this, he aimed a narrow beam of alpha particles at gold.
  • Neils Bohr

    Neils Bohr
    Bohr developed diagrams of an atom that look like a solar system. The "planets" revolve around a "sun". He created a model that focused on electrons.
  • Schrödinger

    Schrödinger developed a math equation to explain motions of electrons in atoms. This created the electron cloud model.
  • Ernest Marsden

    Ernest Marsden
    Ernest Marsden was one of Rutherfords students. Rutherford asked him to find out what happens to alpha particles when they pass through a thin sheet of gold.
  • James Chadwick

    James Chadwick
    James Chadwick confirmed the existence of neutrons. In order to prove this, he attcaked the alpha rays coming out of radioactive material on a Beryllium atom and observed the results. He discovered that Beryllium becomes radioactive for a short time and releases material rays containing neutral particles.
  • Louis de Broglie

    Louis de Broglie
    Broglie believed that moving particles have some properties of waves. His ideas were supported.
  • Heisenberg

    Heisenberg created the Uncertainty Principle, which stated that the accuracy with which properties of atoms and particles can be determined simultaneously. He also invented the first version of the Matrix Mechanics.
  • Bernard Pullman

    Bernard Pullman
    Pullman created a new field of Quantum Biochemistry. He also predicted the carcinogenic properties of aromatic hydrocarbons.