Matter+and+the+Periodic+Table+2

Symbols and Formulas (Pg. 51-52)
By:Gabriel Hannawi
 * Chemists use chemical symbols to represent elements, and chemical formulas to represent compounds
 * The symbols used today for elements are based on a system developed by Swedish chemist Jöns Jacob Berzelius
 * Each element is represented by a one or two letter chemical symbol
 * Chemical symbols provide a shorthand way of writing chemical formulas, such as H2O or C12H22O1

John Dalton's Periodic Table of 1808


(Pgs. 107-108 by Erin Cropanese)

__Rutherford's Gold-Foil Experiment__ [| http://www.youtube.com/watch?v=5pZj0u_XMbc]
 * 1911 he decided to test the current theory of atomic structure
 * he used massive alpha particles and shot a narrow beam of them at a very thin gold foil
 * he expected them to pass through easily with only slight reflection because of positive charge though to be spread out in the gold atoms
 * the results were that the great majority of the alpha particles passed straight through the gold atoms without deflection
 * also, a small fraction of them bounced straight back toward the source and the others bounced off at large angles

 

__ Rutherford Atomic Model __ __Nucleus:__ the tiny central core of an atom and is composed of protons and neutrons
 * Rutherford proposed a new theory of the atom
 * he proposed that the atom is mostly empty space (explains the lack of deflection of most of the particles)
 * he concluded that all positive charge and almost all the mss are concentrated in a small region that has enough positive charge to account for the deflection of some of the alpha particles-> called the NUCLEUS
 * atom model known as the nuclear atom
 * protons and neutrons located in the nucleus
 * the electrons are distributed around the nucleus and occupy almost all the volume of the atom
 * nucleus is tiny compared to the whole atom
 * his model turned out to be incomplete and has since been revised to explain chemical properties of elements