Binary Molecular Compounds Two elements, usually nonmetals Familiar compounds use common names: NH 3 CH 4 H 2 O **most are named in a systematic way

1.Element with the lower group number in the periodic table is the first word in the name (exception: when the compound contains oxygen and a halogen, the halogen is named first) 2.If both elements are in the same group, the one with the higher period number is named first

3.The second element is named with its root and the suffix –ide 4.Use Greek numerical prefixes to indicate the number of atoms of each element in the compound. -The first word has a prefix only when more than one atom -the 2 nd word always has a numerical prefix 5. Drop –o or –a from prefix if two vowels together. Example: Monoxide

Prefixes for Binary Molecular Compounds NumberPrefix 1Mono- 2Di- 3Tri- 4Tetra- 5Penta- 6Hexa 7Hepta- 8Octa- 9Nona- 10Deca-