2. Chemical Nomenclature (or how we name compounds!) 1. binary ionic (cation + anion) 2. molecular (covalent) compounds (anion + anion) 3. ternary ionic (cation + polyatomic) 4. acids (H + + anions) Four types of chemical compounds:

3. Binary Ionic Compounds Writing: - compounds composed of two elements - net ionic charge must be zero - example: Ca 2+ + Br - = CaBr 2 - crisscross method: Ca 2+ Br -

4. Naming binary ionic compounds: - work backwards: K 3 N = K + + N 3- = “potassium nitride” CuS = Cu 2+ + S 2- =“copper (II) sulfide” Remember! It’s transitional.

5. Molecular Compounds composed of two non-metallic elements ionic charges are not used to assign formulas or name them names all end in –ide prefixes used in naming these compounds: mono- 1penta- 5octa- 8 di- 2hexa- 6nona- 9 tri- 3hepta- 7deca- 10 tetra- 4

6. Examples: CCl 4 = carbon tetrachloride OF 2 = oxygen difluoride CO = N 2 O = phosphorous trichloride = Cl 2 O 8 = SO 3 = dinitrogen tetroxide = S 2 Cl 2 = carbon monoxide dinitrogen monoxide PCl 3 dichlorine octoxide disulfur dichloride sulfur trioxide N2O4N2O4

7. Polyatomic Ionic Compounds Compounds that contain atoms of three different elements Usually contain a polyatomic ion √ Write the formula for each ion (symbol and charge) then balance the charges √-ate and –ite on the end indicate that the compounds contain a polyatomic ion that contains oxygen

8. Only two polyatomic ions end in –ide: OH - (hydroxide) CN - (cyanide) Examples: Ca 2+ + NO 3 - Ca(NO 3 ) 2

9. You do these: potassium (K + ) sulfate (SO 4 2- ) Magnesium (Mg 2+ ) hydroxide (OH - ) NH 4 + + SO 3 2- calcium ion + phosphate ion K 2 SO 4 Mg(OH) 2 (NH 4 ) 2 SO 3 Ca 3 (PO 4 ) 2

10. Naming Acids Acids are compounds that produce hydrogen ions in water You need to memorize these: HClhydrochloric acid H 2 SO 3 sulfurous acid H 2 SO 4 sulfuric acid HNO 3 nitric acid H 3 PO 4 phosphoric acid H 2 CO 3 carbonic acid