Atomic model

Atomic Theories

By anaglassmyer
  • 400

    BC Democritus Theorizes about Atomos

    BC Democritus Theorizes about Atomos
    Democritus (400 BC) questioned whether matter could be divided down forever or if there was a limit. He determined there was a limit, which was indivisible, and named it atomos, meaning, "not to be cut."

  • Dalton's Experiments Lead to Acceptance of Atoms

    Dalton's Experiments Lead to Acceptance of Atoms
    John Dalton, theorized that all elements were composed of atoms and atoms of the same element are exactly alike. His research was backed by careful research.

  • J.J. Thomson Discovers Subatomic Particles

    J.J. Thomson Discovers Subatomic Particles
    Thomson (1897) theorized that an atom was not a solid sphere or indivisible, but made up of smaller particles. He thought positive and negative were all mixed together to create a neutral substance. This is referred to as the Plum Pudding Model.

  • Rutherford

    Rutherford
    Ernest Rutherford fired positively-charged particles are a thing sheet of gold foil. Most went through, but some repelled off. HE concluded that a substance is mostly empty space. From this, he theorized that atoms have a central positive nucleus and orbiting negative electrons.

  • Bohr Model Developed

    Bohr Model Developed
    Published in 1913, Bohr's atomic model is very similar to the planetary model currently in existence. He thought that neutrons and protons made up a nucleus, and electrons are held in orbit around the nucleus by electrical force.

  • Erwin Schrodinger

    Erwin Schrodinger
    Erwin Schrodinger developed a mathematical model for the distribution of electrons in an atom. This method does not give the exact location of an electron, but the probability of an electron being in a certain region.