1. Molecular Compounds Held together by Covalent bonds. –Between two or more non-metal elements. –Sharing of electrons –Name using prefixes. Subscripts after the element symbol tell you the prefix to use Examples: –H 2 O dihydrogen monoxide –C 2 H 4 dicarbon tetrahydride –SO sulfur monoxide

2. Naming Molecular Compounds Begin by writing the name of the first element. Add prefixes to each name which tell you how many of that atom are in the molecule. Change end of 2 nd element to -ide –If there is only one atom of the first element in the molecule you can leave out the “mono” prefix on the first element only. Prefix Definitions Mono = 1 Di = 2 Tri = 3 Tetra = 4 Penta = 5 Hexa = 6 Hepta = 7 Octa = 8 Nona = 9 Deca = 10

3. Examples P 2 S 3 diphosphorus trisulfide CO carbon monoxide N 2 O 4 dinitrogen tetraoxide C 2 O 2 dicarbon pentoxide