Atomic Theory

By kengan1
  • 364

    Aristotle

    Aristotle
    Introduction:
    1) One of the most influential philosopher
    2) wrote extensively on many subjects, including politics, ethics, nature, physics, and astronomy.
    3) Most of his writing have been lost through the ages. Idea:
    He claimed that there was no smallest part of matter and that different substances were made up of proportions of fire, air, earth, and water.
  • 460

    Democritus

    Democritus
    His ideas that were contributed to atomic theory:
    1) Matter is composed of empty space through which atoms move.
    2) Atoms are solid, homogenous, indestructible, and indivisible.
    3) Different kinds of atoms have different sizes and shapes.
    4) The differing properties of matter are due to the size, shape, and movements of atoms.
    5) Apparent changes in matter result from changes in the groupings of atoms and not from changes in the atoms themselves.

  • Dalton's Atomic Theory

    Dalton's Atomic Theory
    Dalton developed useful theory of atom.
    1) all matter is composed of extremely small particles called atoms.
    2) all atoms of given element are identical, having the same size, mass, and chemical properties. Atoms of specific element are different from those of any other element.
    3) Atoms cannot be created, divided into small particles, or destroyed.
    4) Different atoms combine in simple whole number ratios to form compounds.
    5) In a chemical reaction, atoms are separated, combined, or rearranged.

  • JJ Thomson

    JJ Thomson
    1) In 1897, the British physicist Joseph John (J. J.) Thomson (1856–1940) discovered the electron in a series of experiments designed to study the nature of electric discharge
    2) In 1904, Thomson suggested a model of the atom as a sphere of positive matter in which electrons are positioned by electrostatic forces.

  • Ernest Rutherford

    Ernest Rutherford
    1) Ernest Rutherford publishes his atomic theory describing the atom as having a central positive nucleus surrounded by negative orbiting electrons.
    2) This model suggested that most of the mass of the atom was contained in the small nucleus, and that the rest of the atom was mostly empty space..
    3)his experiment involved the firing of radioactive particles through minutely thin metal foils (notably gold) and detecting them using screens coated with zinc sulfide (a scintillator).