Image

Atomic Theory

By dylanrenick
  • 460 BCE

    Democritus

    Democritus
    Democritus was the first to ever conduct experiments on atomic theory. He did many experiments but his most well known was his seashell experiment. Democritus would take a seashell and break it in half, and then again and again until it go down to a fine dust which he could not break. He called these discoveries atoms, which is Greek for indivisible. These atoms where believe to be the building blocks of all things. He said that the were hooked together so tightly, nothing could break them.

  • John Dalton

    John Dalton
    John Dalton was a meteorologist and a chemist. His experiments and his atomic theory started from him witnessing things while writing down the weather. He realized water evaporates into the air, that means it shares the same space as the air. Knowing two solids could not share the same place he conducted many experiments to prove his thoughts. Dalton said that all atoms of a given element are identical in mass and properties and that a chemical reaction is a rearrangement of atoms.

  • J.J. Thompson

    J.J. Thompson
    J.J. Thompsons main part in the help towards atomic theory today was the discovery of the electron in 1897. He experimented with a Crookes, or cathrode ray tube. While doing this experiment he proved the cathrode Rays are negatively charged. His first model showing the negative and positive charges of atoms was made from dough, raisins and pudding.

  • Ernest Rutherford

    Ernest Rutherford
    Rutherford overturned J.J. Thompsons plum pudding model in 1911 because he proved that all he matter of an atom was stored in its tiny, compact nucleus. He proved this with his famous gold foil experiment where he demonstrated the atom as a heavy nucleus, with electrons around it.

  • Niels Bohr

    Niels Bohr
    Niels Bohr was the first to ever prove the electrons travel in a separate border around the nucleus. His biggest contribution to the atomic theory was his famous atomic model, the Bohr Model. He created this with the help of J.J. Thompson and Rutherford by his side. The Bohr Model shows the atom with a tiny, positively charge nucleus surrounded by electrons on the outside.