1. Hotdogs contain many chemical additives Sodium nitrite Preservative and colour enhancer Sodium phosphate Binding agent Sodium erythrobate Preservative

2. Nitrites are not all bad news... Research suggests that sodium nitrite may help protect heart tissue after a heart attack or heart transplant Nitrites and nitrates occur naturally in soil and are important plant nutrients

3. Polyatomic Ions A polyatomic ion is an ion that consists of a stable group of several atoms acting together as a single charged particle. The ionic charge of a polyatomic ion is shared over the entire ion rather than being on just one atom 3- Phosphate Ion

4. Formulas and Charges of Common Polyatomic Ions Name of Polyatomic Ion Ion FormulaIonic Charge Nitrate ionNO 3 - - 1 Nitrite ionNO 2 - - 1 HydroxideOH - - 1 CarbonateCO 3 2- - 2- 2 SulfateSO 4 2- - 2 PhosphatePO 4 3- - 3 AmmoniumNH 4 + + 1

5. Naming Compounds involving Polyatomic Ions Write the name of the compound Fe(NO 3 ) 3 Step 1: Write the name of the metal and check whether it has more than one possible ionic charge. Iron has two possible charges (+2 and +3) Step 2: Determine the ionic charge of the metal. Fe(NO 3 ) 3 x + 3(-1) = 0 x = + 3 Step 3: Write the name of the compound with the Roman numeral if necessary. The name of Fe(NO 3 ) 3 is iron (III) nitrate.

6. Writing Formulas for Compounds Containing Polyatomic Ions What is the chemical formula of copper (II) nitrate? Step 1: Write the symbol of each ion, with its charge. Cu 2+ (NO 3 ) - Step 2: Crisscross the numbers of the ionic charges so that they become subscripts. Cu 2+ (NO 3 ) - Step 3: Write any necessary subscripts after the brackets around each ion. The formula of copper (II) nitrate is Cu(NO 3 ) 2

7. What is the most common ending for the name of.... A) a polyatomic anion? “ –ate” (nitrate, chlorate, sulfate, phosphate) B) an anion made up of only one element? “ –ide” (nitride, chloride, sulfide, phosphide)