Polyatomic Ions Thursday, October 12, 2017 Objective: I will learn different polyatomic ions, and how they form compounds Entry Task - Chem Catalyst 22

Definition Polyatomic ions - An ion composed of a group of atoms with an overall positive or negative charge. Most polyatomic ions are anions (one exception is NH4+, a cation). poly - many atomic - atoms

2 Games Play Ionic Grid with your lab group - 20 minutes Return cards to teacher Get one new card Play “3-minute Bonding” You may need more than 2 people to form a real compound Each person in the group writes the cation, anion, chemical formula, and point value down (1 pt/card in compound). Leave chemical name for later As soon as all group members record the compound, break apart and find new compound When you hear “SWITCH”, trade cards with someone

Definition Polyatomic ions - An ion composed of a group of atoms with an overall positive or negative charge. Most polyatomic ions are anions (one exception is NH4+, a cation). poly - many atomic - atoms How can you tell if an ionic compound contains a polyatomic ion? What naming patterns did you notice during the game?

Polyatomic Naming Patterns Ions that differ only by number of oxygen atoms follow a pattern: NO2- - nitrite NO3- - nitrate PO33- - phosphite PO43- - phosphate ClO4- - perchlorate ClO3- - chlorate ClO2- - chlorite ClO- - hypochlorite Stem comes from non-oxygen atom (nitrogen = nitr-, phosphorus = phosph-, chlorine = chlor-) If two ions, higher # of oxygens ends in -ate, and lower ends in -ite If 4 ions: per-stem-ate stem-ate stem-ite hypo-stem-ite

Exit Task What is the NAME of the compound Be(NO3)2? What ions are present in this compound and what are the charges on the ions?