Chemical Formulas Outline

1.         Definitions

            a.         Atom: Electrically neutral form of element

            b.         Ion: Element with an electric charge

            c.         Isotope: forms of element with differing numbers of neutrons

            d.         Allotrope: forms of element with differing molecular structure

            e.         Diatomic: elements that form 2 atom molecules

            f.         Polyatomic Ion: compounds with electric charges

2.         Properties of Compounds

            a.         Differ from elements

            b.         Properties are unique

            c.         More stable than elements

            d.         Form when atoms collide

3.         Octet Rule

            a.         Atoms stable when outer level has 8 electrons

            b.         Compound is stable when all outer levels have 8 electrons

            c.         Noble gas configuration

4.         Ways to Achieve an Octet: Ionic Compound

            a.         One element has a stronger attraction for electrons

            b.         Electrons transfer to form ions

            c.         Ions have noble gas configuration

            d.         Ions attract each other

5.         Results of Ion Attraction

            a.         Strong inter-particle forces

            b.         Form ionic bond

            c.         Well organized crystals

6.         Properties of Ionic Compounds

            a.         Solids at room temperature

            b.         High melting points

            c.         Rigid and brittle

            d.         Dissolve easily in H₂O

            e.         Dissociate to form ions, conduct electricity

7.         Ways to Achieve an Octet: Molecular Compound

            a.         Both elements have similar attraction for electrons

            b.         Neither can take electrons

            c.         Electrons shared to produce noble gas configuration

            d.         Form covalent bond

            e.         Covalent compounds called molecules

8.         Properties of Molecular Compounds

            a.         Weak inter-particle forces

            b.         Tend to be liquids or have low melting points

            c.         Do not dissociate, do not conduct

            d.         Rarely dissolve in water

9.         Symbols: IUPAC Named Elements

            a.         Shorthand for the element

            b.         Two letters

            c.         First is upper case

            d.         Second in lower case

10.       Symbols: IUPAC Unnamed Elements

            a.         Three letters

            b.         First upper case, others lowercase

            c.         Ex. 118 is UnUnOctium or Uuo

11.       Chemical Formula

            a.         Combination of symbols and number

            b.         Representation of compound

            c.         Shows elements, number of atoms, and ratio

            d.         Positive element is listed first

12.       Compound Types

            a.         Ionic: gives lowest ratio

            b.         Molecular: gives 1 molecule

13.       Oxidation Numbers

            a.         Atoms combine to form stable octets

            b.         Oxidation number: electrons gained, lost, or shared

            c.         Equals the ion charge

14.       Ion Tables

            a.         Type I: elements with 1 oxidation number

            b.         Type II: elements with more than 1 oxidation number

            c.         Type III: polyatomic ion

15.       Writing Formulas

            a.         Write the symbols with oxidation numbers

            b.         Positive goes first

            c.         If polyatomic ions involved enclose the ions in parentheses

            d.         Find LCM of oxidation numbers

            e.         Divide LCM by oxidation number to determine number of atoms

            f.         Write numbers to lower right of symbols

16.       Naming Compounds

            a.         Use flowchart for inorganic compounds

            b.         Special rules used for organic compounds