H (2.1) ELECTRO NEGATIVITY : a relative measure of an atom’s attraction for electrons. Higher the number, tighter the hold of electrons He (0) L (1.0) Be (1.5) B (2.0) C (2.5) N (3.0) O (3.5) F (4.0) Ne (0) Na (.9) Mg (1.2) Al (1.5) Si (1.8) P (2.1) S (2.5) Cl (3.0) Ar (0) HISTORY • Began in Greece • Plato’s Bounding Triangle Theory • Democritus: 1 basic shape, end point is the “atoma” • Alchemy societies hid from the church. 4 Principles : Unity of the four basic elements / All elements had a soul // Transmutation (universal medicine) // PEOPLE TO KNOW Dalton : Atomic Theory. Valence Theory (hook on the atoms). Atomic weight, atoms= hard spheres. Faraday : Electricity can cause reactions, be produced by them and everything is made up of it Mendeleyev: Organized elements Wohler : “Created life” Mosely : Cathode ray, found Proton Rutherford : Gold foil, atom mostly empty space, mini solar system
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This note was uploaded on 04/07/2008 for the course CHEM 100 taught by Professor Adamski during the Spring '08 term at Adelphi.