1. Naming Ionic Compounds There can be more than one compound composed of the same elements Compound names must distinguish among these compounds How can you tell if a compound is an ionic compound? (What kinds of elements are joined by ionic bonds?) (How can you tell if an element is a metal or a non-metal?)

2. Binary Compounds Binary compounds are made of only two elements Binary compound names have a predictable pattern Name = name of the cation + name of the anion ( -ide ) Sodium chloride NaCl Potassium iodide KI Calcium oxide CaO Magnesium bromide MgBr 2

3. Metals with Multiple Ions Many transition metals can form ions with different charges Iron: +2 or +3 Copper: +1 or +2 Names for these cations use Roman numbers to show the charge: Iron (III) Sometimes the suffixes -ous and -ic are used FeO Iron two oxide Ferrous oxide Fe 2 O 3 Iron three oxide Ferric oxide

4. Polyatomic Ions “Many-atoms” covalently bonded acting as a single ion Most are anions The exception is NH 4 + “ammonium” There is a table in the reference sheet with the compositions and names of common polyatomic ions… Names for compounds with polyatomic ions are constructed the same as those for binary compound Name of cation + name of anion NH 4 NO 3 Ammonium nitrate

5. Ionic Formulas Ionic formulas show the ratio of cations to anions This ratio depends on the charges on the ions The number of each ion in the compound is shown using a subscript number Remember – the compound must be electrically neutral Two +1 ions are required to balance one -2 anion: Na 2 S Three -1 anions are required to balance one +3 cation: AlCl 3

6. Molecular Compounds Names and formulas describe the number and type of atoms in the molecule The “most” metallic element is named first Farther to the left Farther to the bottom Prefixes show the number of atoms of each element How can you tell if a compound is molecular? (What kinds of bonds join the atoms of a molecule?) (What kinds of elements are joined by covalent bonds?) (How can you tell if an element is a metal or a non-metal?)