Chemical nomenclature is the system used to name chemical compounds in order to distinguish them from each other. There are different naming rules for ionic compounds versus molecular compounds. Binary ionic compounds follow the rules of naming the metal first followed by the nonmetal with an "ide" ending, such as NaCl for sodium chloride. Binary molecular compounds use prefixes to indicate the number of atoms of each nonmetal, such as nitrogen dioxide (NO2) or phosphorus trifluoride (PF3). Some common molecular compounds have non-systematic names like water (H2O) or ammonia (NH3).

1. CHEMICAL NOMENCLATURE

2. Chemical Nomenclature System of names used to distinguish compounds from each other and the rules needed to devise these names

3. Ionic vs Molecular compounds Separate system for each, so the first step is to identify whether the compounds are ionic or molecular Here are two general rules: Ionic= metal + non-metal Molecular=non-metal + metal

4. Binary ionic compounds Binary=two A binary compound is a compound in which only two elements are present A binary ionic compound is an ionic compound in which one element present is a metal and the other is a non-metal, such as NaCl

5. Rules for naming binary ionic compounds First word=name of metal Second word=stem name of nonmetal + ide Let’s try a few: NaCl Sodium chloride MgF 2 Magnesium flouride Na 2 O Sodium oxide

6. Binary molecular compounds A molecular compound in which only two non-metallic elements are present Rule: First word: numerical prefix + full name of nonmetal Second word: numerical prefix + stem name of second nonmetal + ide

7. Binary molecular compounds Common numerical prefixes: Mono=1 Di=2 Tri=3 Tetra=4 Penta=5 Hexa=6

8. Binary Molecular Compounds Let’s try a few: N 2 0 5 Dinitrogenpentoxide PF 3 Phosphorous trifluoride SiCl 4 Silicon tetrachloride

9. Binary Molecular Compounds that have Common Names Common name: not based on IUPAC* rules and has no information about composition of compound H 2 O=water H 2 O 2 =hydrogen peroxide NH 3 =ammonia CH 4 =methane *IUPAC=International Union of Pure and Applied Chemistry