A Brief History of the Atom Part 1 (PDF)

A Brief History of the Atom Part I SOL style! This is a brief summary of the atom based upon the SOL scientists that you need to know. It is by no means comprehensive, and is not in a chronological order. It is simply meant as a study guide to those scientists covered by the SOL standards A. **...

A Brief History of the Atom Part I SOL style! This is a brief summary of the atom based upon the SOL scientists that you need to know. It is by no means comprehensive, and is not in a chronological order. It is simply meant as a study guide to those scientists covered by the SOL standards A. **Democritus** a. **Theory of the Atom or "Theory of Atomos**"- Theory that all matter was made up of individual and indestructible particles b. Created the **Solid Sphere Model** of the atom http://1.bp.blogspot.com/-ZcbGcqQLLrc/TjBx2\_DVA1I/AAAAAAAAABk/WTazighMILA/s1600/democritus.png B. **Antoine Lavoisier** c. Gave us the **Law of Conservation of Mass** i. Widely used law throughout Chemistry, used in Balancing equations, calculating theoretical yield, etc. ii. Mass of Reactants going in = Mass of Products formed C. **John Dalton** d. Created the first **Atomic Theory** by bringing together all the current ideas along with his own research e. 5 Major points to know regarding his theory iii. **Atoms are indivisible and indestructible** 1. Later proven false by the discovery of subatomic particles iv. **Atoms of a given element are identical** 2. Proven false due to the creation of isotopes and ions v. **Atoms of different elements are different, with different properties** 3. Half true: Atoms of different elements ARE different, but families of elements share similar properties vi. **Law of Conservation of Mass** 4. True. See Lavoisier for more information vii. **Law of Definite Proportions** 5. Daltons contribution, stating "Every compound is made up of fixed proportions of elements by MASS" a. A great example of this is Percent Composition D. **J. J. Thomson** f. Use the **Cathode Ray Tube** to study gases and the beam of energy created when passing an electrical current through a metal plate g. Discovered the **electron** (was originally called a corpuscle) h. Created the **"Plum Pudding" Model** of the atom E. **Ernest Rutherford** i. Use the **Gold Foil Experiment** to examine the structure of the atom viii. Fired Alpha Radiation (see Radiation review) at gold foil and looked at how it was deflected  j. Discovered a very dense and positively charged center which was called the **nucleus** k. Gave us the **"Nuclear" model** of the atom http://inbastudentfinal.weebly.com/uploads/3/0/1/9/30199383/3418935\_orig.jpg l. Also given credit for the discovery of the **proton** F. **Chadwick** m. Discovered the **neutron** by bombarding Beryllium with alpha particles ix. Part of a follow up to Rutherford's experiments on the nucleus