History of the Atomic Theory

  • The Alchemists
    100

    The Alchemists

    One target of the alchemists was to change or "transmute" ordinary metals into valuable metals like gold.
  • Democritus
    400

    Democritus

    He believed that atoms were the smallest things in the universe and that they could not be broken up. He thought that there was just empty space between the atoms, nothing else.
  • John Dalton

    John Dalton

    He thought that atoms could be distinguished by their weight. His theory had a number of principle rules.
  • J.J. Thomson

    J.J. Thomson

    He discovered that there are more things inside atoms. They are now known to us as electrons.
  • Ernest Rutherford

    Ernest Rutherford

    He established that the nucleus was: very dense, very small and positively charged. He also assumed that the electrons were located outside the nucleus.
  • Neils Bohr

    Neils Bohr

    He created the Bohr model of the atom with the atomic nucleus at the centre and electrons in orbit around it, which he put in comparison to the planets orbiting the Sun.