Atomic theory

The Atomic Theory

By Simon Lopez
  • 520 BCE

    Leucippus 5th century BCE

    Leucippus 5th century BCE
    He was a philosopher who was the earliest Greek to develop the theory of atomism—the idea that everything is composed entirely of various imperishable, indivisible elements called atoms. Leucippus often appears as the master to his pupil Democritus, a philosopher also touted as the originator of the atomic theory.
  • 460 BCE

    Democritus 460—370 B.C.E.

    Democritus 460—370 B.C.E.
    The theory of Democritus said that everything is composed of "atoms", which are physically indivisible; that between atoms, there lies empty space; that atoms are indestructible, and have always been and always will be in motion; that there is an infinite number of atoms and of kinds of atoms, which differ in shape and size.

  • John Dalton 6 September 1766 – 27 July 1844

    John Dalton 6 September 1766 – 27 July 1844
    He found that: elements are made of extremely small particles called atoms. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties. Atoms cannot be subdivided, created, or destroyed. Atoms of different elements combine in simple whole-number ratios to form chemical compounds. In chemical reactions, atoms are combined, separated, or rearranged.

  • Eugen Goldstein 5 September 1850 – 25 December 1930

    Eugen Goldstein 5 September 1850 – 25 December 1930
    He became known for the discoverer of anode rays, and is sometimes credited with the discovery of the proton.

  • J.J. Thomson 18 December 1856 – 30 August 1940

    J.J. Thomson 18 December 1856 – 30 August 1940
    In 1897 was the first to suggest that one of the fundamental units was more than 1,000 times smaller than an atom, suggesting the subatomic particle now known as the electron. He also won a Nobel Prize in 1906

  • Ernest Rutherfrod 30 August 1871 – 19 October 1937

    Ernest Rutherfrod 30 August 1871 – 19 October 1937
    He became known as the father of nuclear physics. He started his research with J.J. Thomson it was about the effect of x-rays in gasses. He won a Nobel Prize in 1908 because of his disovery of the neutron

  • Niels Bohr 7 October 1885 – 18 November 1962

    Niels Bohr 7 October 1885 – 18 November 1962
    When Bohr proposed his atomic model including the electron many of the young scientists and physicists said it was a breakthrough. He also made an institute for theoretical physics

  • James Chadwick 20 October 1891 – 24 July 1974

    James Chadwick 20 October 1891 – 24 July 1974
    He was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. He was knighted in England in 1945 for his achievements in physics.