3. Monday, Feb. 3 rd : “A” Day Tuesday, Feb. 4 th : “B” Day Agenda  Homework questions/collect  Finish Sec. 5.3: “Names & Formulas of Ionic Compounds”  In-Class: Ionic Bonding Activity  Homework: Sec. 5.3 review, pg. 180: #1-8 “What is a Polyatomic Ion?” WS Concept Review: “Names & Formulas of Ionic Compounds”

4. Homework  “What is an Oxidation Number?”  “How are Chemical Compounds Named?”  “Naming Ionic Compounds”  Questions?  Hand In

5. Quick Review…  Remember, a binary compound is made of just 2 elements.  The simple cation is the positively charged metal ion and is named first.  The simple anion is the negatively charged non-metal ion and is named last.  But, not all ionic compounds are binary compounds…

6. Polyatomic Ions  Instead of having ions made of a single atom, many ionic compounds have groups of atoms that are ions.  A simple ion is monatomic, which means “one-atom.”  The prefix “poly” means many or more than one.  Polyatomic ion: a charged group of 2 or more bonded atoms that can be considered a single ion.

7. Polyatomic Ions  Table 2 on Pg. 178 in your book lists some polyatomic ions. There are additional polyatomic ions on the back of the handout I gave you. Examples: CO 3 2- : carbonate ion OH - : hydroxide ion PO 4 3- : phosphate ion  The charges on polyatomic ions are not found on any one atom. Instead, they are spread across the entire group of covalently bonded atoms.

8. Naming Polyatomic Ions  Many polyatomic ions contain oxygen.  The endings –ite and –ate mean there is oxygen present in the polyatomic ion.  -ite means less oxygen (think LITE)  -ate means more oxygen (I ATE more)  Examples: SO 3 2- is sulfite (3 oxygen atoms = less oxygen) SO 4 2- is sulfate (4 oxygen atoms = more oxygen)

9. Naming Polyatomic Ions  If there is hydrogen in the polyatomic ion, the ion’s name starts with hydrogen.  The prefixes mono- and di- are used to show the number of hydrogen atoms. “mono” means 1 “di” means 2  Examples: HSO 4 2- : monohydrogen sulfate (1 hydrogen) H 2 SO 4 - : dihydrogen sulfate (2 hydrogen)

10. Naming Polyatomic Ions  The prefix thio- means: “replace an oxygen atom with a sulfur atom”  Example: K 2 SO 4 : potassium sulfate K 2 S 2 O 3 : potassium thiosulfate (1 oxygen atom was replaced with a sulfur atom)

11. Hints for writing formulas with polyatomic ions 1.Find the charges on the cation and the anion. 2.Look at the tables to find the formula for the polyatomic ion. (it can be a cation or an anion) 3.Write the formula so that the charges balance out to zero. 4.If more than 1 polyatomic ion is needed to balance the charge, put the polyatomic ion in ( ) and add a subscript outside the ( ).

12. Sample Problem A: pg 179 Write the formula for iron(III) chromate. 1.Find the charge for the iron(III) cation: Fe 3+ 2.Find the formula and charge for the chromate polyatomic ion from the table: CrO 4 2- 3.Balance charges of cation and anion and write the formula: Fe 3+ CrO 4 2- Fe 2 (CrO 4 ) 3

13. Practice  Write the formulas for the following ionic compounds: a) Calcium cyanide Ca(CN) 2 b) Ammonium sulfate (NH 4 ) 2 SO 4 c) Calcium acetate Ca(CH 3 COO) 2 d) Rubidium thiosulfate Rb 2 S 2 O 3

14. Ionic Bonding Activity  In this activity, you will work with a partner of your choice to construct various ionic compounds using the “ion squares” provided.  Each square contains a cation or anion.  Working with your partner, construct formulas using the elements listed under “combining substances”.  In addition to the 10 compounds listed on the handout, you need to come up with 5 of your own using the “ion squares”.

15. Ionic Bonding Activity  Use the table of polyatomic ions on page 178 of your textbook and the handouts for help with the names and charges of the polyatomic “ion squares”.  This activity will be graded like a lab, is worth 30 points, and will be due today! Use your time wisely!

16. CombiningSubstancesChemical Formula Name of Compound Aluminum 3 + Bromine 1 - AlBr 3 Aluminum Bromide  You will each need to make a data table to record your data. Sample Data Table

17. Homework  Section 5.3 review Pg. 180: #1-8  “What is a Polyatomic Ion? worksheet  Concept Review: “Names & Formulas of Ionic Compounds” You will need to use your book for the tables on pgs. 162-163 or the handout I gave you for the cations/anions formed. You will need to use the table of polyatomic ions on pg. 178 and the handouts I gave you.