History of the Atomic TheoryHistory of the Atomic Theory

Law of Definite ProportionsLaw of Definite Proportions

A given compound contains the same elements in exactly the same proportions by mass, regardless of the size of the sample or the source of the compound

e.g. NaCl always contains 39.34% by mass of sodium and 60.66% by mass of Chlorine

Law of Conservation of MassLaw of Conservation of Mass

The mass of the products of a reaction The mass of the products of a reaction equals the mass of the reactantsequals the mass of the reactants

e.g. 32 mass units of sulfur and 32 mass e.g. 32 mass units of sulfur and 32 mass units of oxygen react to form 64 mass units of oxygen react to form 64 mass units of sulfur dioxideunits of sulfur dioxide

Law of Multiple ProportionsLaw of Multiple Proportions

The mass ratio for one of the elements that The mass ratio for one of the elements that combines with a fixed mass of another element combines with a fixed mass of another element can be expressed in small whole numberscan be expressed in small whole numbers

e.g. 2 grams of hydrogen combine with 16 e.g. 2 grams of hydrogen combine with 16 grams of oxygen to form water, but 2 grams of grams of oxygen to form water, but 2 grams of hydrogen combine with 32 grams of oxygen to hydrogen combine with 32 grams of oxygen to form hydrogen peroxideform hydrogen peroxide

16:32 = 1:216:32 = 1:2

John DaltonJohn Dalton

http://www.slcc.edu/schools/hum_sci/physics/whatis/biography/dalton.html

John Dalton’s Billiard Ball ModelJohn Dalton’s Billiard Ball Model

http://www.poolndarts.com/index.cfm/fuseaction/Catalog.

Category/categoryID/77.cfm?STLCMPID=1798&engine=adwords!1994&keyword=%28billiard+ball%29&match_type=

Dalton’s Atomic TheoryDalton’s Atomic Theory 1. All matter is made of indivisible and 1. All matter is made of indivisible and

indestructible atoms.indestructible atoms. 2. All atoms of a given element are identical in 2. All atoms of a given element are identical in

their physical and chemical properties.their physical and chemical properties. 3. Atoms of different elements differ in their 3. Atoms of different elements differ in their

physical and chemical properties.physical and chemical properties. 4. Atoms of different elements combine in 4. Atoms of different elements combine in

simple whole-number ratios to form compounds.simple whole-number ratios to form compounds. 5. Chemical reactions consist of the 5. Chemical reactions consist of the

combination, separation, or rearrangement of combination, separation, or rearrangement of atoms.atoms.

J. J. ThomsonJ. J. Thomson

http://www.aip.org/history/electron/jjhome.htm

Plum Pudding modelPlum Pudding model

http://www.nationmaster.com/encyclopedia/Plum-pudding-model

Ernest RutherfordErnest Rutherford

http://www.nationmaster.com/encyclopedia/Ernest-Rutherford

Rutherford’s Gold Foil ExperimentRutherford’s Gold Foil Experiment

Niels BohrNiels Bohr

http://nobelprize.org/physics/laureates/1922/

James ChadwickJames Chadwick

http://www.light-science.com/chadwick.html

Model of the Atom Model of the Atom

http://www.nationmaster.com/encyclopedia/Image:Atom-diagram.png

Louis deBroglie and Erwin SchrodingerLouis deBroglie and Erwin Schrodinger

http://www.britannica.com/nobel/micro/87_61.htmlhttp://www.britannica.com/nobel/micro/531_80.html