The Atoms

By Helinas
  • 400 BCE

    Democritus 460BC-370BC

    Democritus 460BC-370BC
    He was born in Abdera, Greece in 460BC. He lived to be 90 years old, dying in the year 370BC. He studied natural philosophy in Thrace, Athens, and Abdera, Greece. This is Democritus' atomic theory exactly:
    1.All matter consists of invisible particles called atoms.
    2. Atoms are indestructible.
    3. Atoms are solid but invisible.
    4. Atoms are homogenous.

  • John Dalton 1776-2017

    John Dalton 1776-2017
    He created the very first atomic theory that had 4 statements
    1 Atoms are tiny, invisible particles
    2 Atoms of one element are all the same
    3 Atoms of different elements are different
    4 Compound form by combining atoms

  • Goldstein 1850-1930

    Goldstein 1850-1930
    He was a German neurologist and psychiatrist who created a holistic theory of the organism.Used a CRT to study "canal rays" which had electrical and magnetic properties opposite of an electron. Goldstein concluded that in addition to the electrons, or cathode rays, that travel from the negatively charged cathode toward the positively charged anode, there is another ray that travels in the opposite direction, from the anode toward the cathode.

  • JJ Thompson 1856-1940

    JJ Thompson 1856-1940
    He discovered (1897) the electron, a negatively charged part of every atom. Though several alternative models were advanced in the 1900s by Lord Kelvin and others, Thomson held that atoms are uniform spheres of positively charged matter in which electrons are embedded. Popularly known as the plum-pudding model.

  • Ernest Rutherford 1871-1973

    Ernest Rutherford 1871-1973
    Rutherford atomic model, also called nuclear atom or planetary model of the atom, description of the structure of atoms proposed (19119, in which nearly all the mass is concentrated, around which the light, negative constituents, called electrons, circulate at some distance, much like planets revolving around the Sun. The Rutherford model supplanted the “plum-pudding” atomic model.
    Rutherford discover the proton and nucleus

  • Niels Bohr 1885-1962

    Niels Bohr 1885-1962
    Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.
    The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. He had 3 theories
    the one of Atomic model, the Liquid droplet theory, and the Quantum theory.

  • James Chadwick 1891-1974

    James Chadwick 1891-1974
    he proved the existence of neutrons, also he say that Neutrons were found to have the same mass as protons which accounted for more of the mass of the atom and allowed the known mass of an atom and the known mass of its particles to match .Chadwick could tell that the mysterious radiation was neutral because it was not deflected by electric or magnetic fields and it did not invoke the photoelectric effect, unlike standard gamma radiation.