1. Note Guide 4-3 Naming Compounds/Writing formulas Describing Ionic Compounds --name of an ionic compound must distinguish the compound from other ionic compounds containing the same elements. -- the formula of an ionic compound describes the ratio of ions in the compound. Binary Ionic Compound: made from only 2 elements --naming binary compounds easy: cation comes first, then the anion **Remember, the name for the anion uses part of the name of the non metal with the suffix –ide. (see figure 16 on page 171) The cation name is just the name of the metal.

2. Metals with multiple ions --transition metals form more than one type of ion. --EX: Copper with 1+ charge Copper with 2+ charge copper (I) ion copper (II) ion Roman numerals indicate the charge of the ion When writing the formulas, must balance out the ion charge. EX: copper one oxide is Cu 2 O because it takes two Cu 1+ to balance the O 2- ion Polyatomic Ions: --covalently bonded group of atoms that has a positve or negative charge AND acts as one unit --mostly anions (meaning they have a – charge) EX: figure 18 (draw into notes) --parenthesis in a formula indicate a polyatomic ion is included: Fe(OH) 3

3. --what this means is that a polyatomic ion made up of 3 hydroxide (OH) ions bonded to one iron ion. Writing formulas for Ionic compounds --put the cation symbol first, then the anion symbol. --Use subscripts to show the ratio of the ions in the compound. --total charges of the compound is netural EX: Sulfur (gains 2 e-) reacts with sodium (loses one e-) --There must be 2 sodium ions (Na + ) for each sulfide ion (S 2- ) to balance out the charges ….so Na 2 S

4. Day 2