Historical Development of Atomic Theory: Aristotle to Rutherford1. Democritus and Aristotle in 400 B.C.2. Aristotle: matter can be divided into smaller andsmaller particles.3. Democritus: the atom is the smallest unit.4. Aristotle’s theory was most popular.
John Dalton’s Contributions...John Dalton, English school teacher, early 1800’s(1804) revision of atomic theory and modern modelwas begun.His laws attempted to explain chemical reactionsinvolve atoms. 1. Law of conservation of matter 2. Law of constant composition 3. All matter made up of atoms 4. All atoms of a particular element are alike 5. A chemical reaction involves the union or separation of atoms.
JJ Thomson and The Plum Puddling Model of the Atom1. JJ Thomson and E.Goldstein – 19072. Discovered the proton.3. Positive charge.4. Plum pudding model ofthe atom.
Ernest Rutherford andReﬁning The Atomic Model1. Ernest Rutherford- 19092. Gold foil experiment3. Alpha particles4. Revision of the model.
The Quantum Mechanic Model: Beyond The Rutherford Model 1. Quantum Mechanic model: 1910-1930 quantum physics. 2. James Chadwick 1932 discovered the neutron. All these men did their research at the Cavendish Lab in England. “That is how science advances: each new conceptual scheme embraces the phenomena explained by its predecessors and adds to them… like Aristotelianism before it, Newtonianism at last evolved---this time within physics---problems and research techniques which could not be reconciled with the worldview that produced them.” ---from Thomas Kuhn’s The Copernican Revolution.
Unknown Black InksChromatography Some Known Black Inks