www.mindbites.com In this lesson, you will learn the common nomenclature of chemistry. Professor Harman defines and contrasts atoms, molecules, ions, and ionic salts/covalent solids. Then Professor Harman covers written chemical formulas and visual representations of molecules. A molecular formula is a chemical formula that represents the actual number of atoms of each element within a molecule. An empirical formula is a chemical formula of a compound written with the smallest integer ratio of subscripts. Empirical formulas are always used to describe ionic compounds and covalent network solids. Various visual representations of molecules include the ball and stick three dimensional model that closely represents the structure of the molecule, a line drawing that approximates the structure in two dimensional terms, and a shorthand often used by organic chemists. Professor Harman warns that molecules are defined by their unique arrangements of atoms, and a formula can represent many different molecular compounds (known as isomers). Taught by Professor Harman, this lesson was selected from a broader, comprehensive course, Chemistry. This course and others are available from Thinkwell, Inc. The full course can be found at www.thinkwell.com The full course covers atoms, molecules and ions, stoichiometry, reactions in aqueous solutions, gases, thermochemistry, Modern Atomic Theory, electron configurations, periodicity, chemical bonding, molecular geometry, bonding theory …