Naming Binary Molecular Compounds

3 Rules to Name 1. Name the first element using the entire name 2. Second element in the formula- use the root word and end in –ide ex: Oxygen Sulfur Hydrogen Oxide Sulfide Hydride

3. Add a prefix to both words to indicate the number of atoms mono- 6. hexa- di- 7. hepta- tri- 8. octa- tetra- 9. nona- penta- 10. deca-

Exceptions to the rule 1. When the formula contains one atom of the first element, omit mono ex: CO2 Carbon Dioxide Not: Monocarbon Dioxide

2. When the prefix ends in an a or o and the element starts with an o, drop the final vowel in the prefix ex: CO Carbon monoxide Not: Carbon monooxide

Example 1 S4N2 tetra di sulfur nitride nitrogen tetrasulfur dinitride

Example 2 SO3 tri oxygen sulfur tri oxide Only one atom of sulfur - so no prefix needed oxygen sulfur tri oxide

Example 3 P4S5 penta tetra sulfur tetra phosphorus penta sulfide

Example 4 CO mono oxygen NOT monooxide carbon mon oxide Only one atom of carbon - so no prefix needed oxygen NOT monooxide carbon mon oxide

Example 5 NH3 tri hydrogen More Common Name is “ammonia” nitrogen tri Only one atom of nitrogen - so no prefix needed hydrogen More Common Name is “ammonia” nitrogen tri hydride

Example 6 CH4 tetra hydrogen More Common Name is “methane” carbon Only one atom of carbon - so no prefix needed hydrogen Saturated has all H’s (single bonds), unsaturated is missing H’s from the presence of at least one single bond. Saturated is solid at room temp (butter) and not generally good for you (increases bad cholesterol) typically animal fats. Unsaturated is typically liquid at room temperature and a better alternative for you, typically vegetable fats. More Common Name is “methane” carbon tetra hydride

Example 7-9 Example 7: As2O3 Diaresenic trioxide Example 8: N2O5 Dinitrogen pentoxide Example 9: P4O10 Tetraphosphorus decoxide