The Atomic Theory of Matter

  • Jan 1, 1000


    460 - 370 B.C.E.
    Concluded that there is a limit to how far you could divide matter. You would eventually end up with a piece of matter that could not be cut. called it an atom!
    The Greek word “atomos” means not able to be divided or “indivisible.”
    My theory says...
    Atoms are small hard particles
    Made of a single material formed into different shapes and sizes
    They are always moving
    They form different materials by joining together.
  • Dec 1, 1000


    350 B.C.E
    there are five elements:
    These elements make up all substances and they all move to the center of the universe --- which is Earth of course.
  • John Dalton

    John Dalton
    Dalton’s atomic model is called the “Billiard Ball Model.” All substances are made up of atoms which are small particles that cannot be created, divided, or destroyed.
    Atoms of the same element are exactly alike and atoms of different elements are different.
    Atoms join with other atoms to form different substances
    In chemical reactions, atoms are combined, separated, or rearranged.
  • Sir William Crookes

    Sir William Crookes
    This was a glass tube with two electrodes connected to a battery. The vacuum sealed tube allowed Crookes to see a pathway where the electrons traveled!
  • Dmitri Mendeleev

    Dmitri Mendeleev
    I decided to organize the elements discovered thus far by their properties. This was the beginning of the modern periodic table! My periodic table organizes the known elements by their properties of atomic weight and valance (valance electrons are those in the outer shell --- who remembers the "octet rule?")
  • J.J. Thomson

    J.J. Thomson
    Thomson took Crookes’ tube and used a magnet to bend the ray. The ray bent towards the positive side of the magnet. He concluded that the ray must have had a negative charge if it was attracted to the positive side. These negative charges became known as electrons.
  • Ernest Rutherford

    Ernest Rutherford
    An atom has a dense center called the nucleus that has a positive charge!
    Most of an atom is empty space!
    The nucleus has a large mass (well... compared to electrons!!!)
  • Neils Bohr

    Neils Bohr
    Proposed that electrons move in paths at certain distances around the nucleus. Electrons can jump from a path on one level to a path on another level. Planetary Model
    electrons move in circular orbits within specific energy levels
  • James Chadwick

    James Chadwick
    Discovered neutrons, neutral particles in the nucleus of an atom using Joliot-Curie Experiments. I based on my theory on their experimental evidence.