Atom

Chemistry!

  • Democritus
    370

    Democritus

    matter is not divisible, but made up of particles called "atomos"
  • John Dalton

    John Dalton

    Matter is composed of atoms. All atoms of an element are identical. Atoms cannot be created or destroyed.
  • Dmitri Mendeleev

    Dmitri Mendeleev

    sorts elements by mass and similarities
  • J.J. Thomson

    J.J. Thomson

    proves Dalton's theory has flaws...atoms can be broken up into subatomic particles....(Electron)