Development of Atomic Model

By SeanP-atomic
  • 460 BCE

    Democritus

    Democritus was born around 460 or 490 BCE. He was taught by Leucippus, who shared his speculation on the existence of atoms but the two's ideas started with different ideas. He was also so hated by Plato he wanted all of Democritus' books burned, however he was known to his fellow northern-born Aristotle.

  • John Dalton

    John Dalton was born in Eaglesfield, England. He is best known for his work contributing to the modern atomic model. He explained the behavior of atoms in the measurement of weight. His atomic theory is: 1) All matter is made of atoms. Atoms are indivisible and indestructible.
    2) All atoms of a given element are identical in mass and properties
    3) Compounds are formed by a combination of two or more different kinds of atoms.
    4) A chemical reaction is a rearrangement of atoms.

  • J. J. Thompson

    Joseph John Thomson was born in Cheetham Hill, a suburb of Manchester. He is most famous for discovering the electron, by first firing a cathode ray from an electrode (by providing electricity(cathode rays are rays of electrons)), a through a hole in another electrode. He then realized that the stuff in the ray had an electric charge, specifically negative. He also confirmed that they existed in all atoms by testing different material electrodes.

  • Ernest Rutherford

    Ernest Rutherford was born in Brightwater, New Zealand. He performed his most famous experiment with Hans Geiger and Ernest Marsden. In the experiment he fired alpha particles (helium nuclei) at an extremely thin sheet of gold, with some bouncing completely off, some being distorted a little in their path, and some going straight through.

  • Niels Bohr

    Niels Bohr was born in Copenhagen, Denmark. Niels Bohr was one of the very influential scientists of the 19th century. He is best known for his contributions to QED, or quantum theory.

  • James Chadwick

    James Chadwick was born in Bollington, United Kingdom. Until he came around, people thought of a plum pudding model of the atom, with a positive dough around electrons. But he bombarded beryllium atoms with alpha particles. An unknown radiation was produced and dubbed the neutron.