1. Bell Ringer Use your oxidation sheet to write the formula or name the following: Barium Phosphite Rubidium Sulfide Na 3 PO 4 Fe 2 (CO 3 ) 3

2. Chapter 4 “Chemical Names and Formulas” Modified and adapted from Pre-AP Chemistry Charles Page High School Stephen L. Cotton H2OH2O

3. The student will: SWBAT’2  classify the type of bond that forms between two given elements.  write the chemical symbol/name given the name/chemical symbol of an element.  classify a given compound as ionic or molecular.  given a sheet of common ions, represent an ionic compound in multiple ways--using words and chemical formula.  represent a molecular compound in multiple ways-- using words, chemical formula and diagrams.  represent the seven common diatomic molecules in multiple ways-- using words, chemical formula and diagrams.

4. l 4: Same as a 3.0 but I can make inferences & application to the SWBAT’s l 3: I COMPLETELY understand all parts of the SWBAT l 2: I understand MOST of the SWBAT’s with teacher help l 1:I understand a little of the SWBAT’s but need teacher help l 0:I do NOT understand any part of the SWBAT’s and need help!

5. Section 4.2 Naming and Writing Formulas for Ionic Compounds l OBJECTIVES: –Apply the rules for naming and writing formulas for binary ionic compounds.

6. Section 4.2 Naming and Writing Formulas for Ionic Compounds l OBJECTIVES: –Apply the rules for naming and writing formulas for compounds containing polyatomic ions.

7. Video l Before you go through these notes, watch the following video to find/identify the different ions identified. l Writing Ionic Formulas: Introduction Writing Ionic Formulas: Introduction

8. WRITING FORMULAS Write symbols & oxidation # of the cation & anion –ex. a: Sodium Chloride  Na +1 & Cl -1 –ex. b: Aluminum Oxide  Al +3 & O -2

9. WRITING FORMULAS Do the oxidation #’s = 0? –(net charge must = 0 in proper formula) –Yes; rewrite symbols without oxidation #’s –ex. a: (+1) + (-1) = 0  NaCl

10. WRITING FORMULAS Do the oxidation #’s = 0? –Al +3 O -2 –No; how many Al +3 ‘s will it take to cancel out O -2 ‘s charge? –Need Balanced Ion Pairs! –2 x (Al +3 ) = +6 –3 x (O -2 ) = -6 –  Al 2 O 3 = 0

11. Video l Watch the following video for how to use the crossover method. l Chemistry Lesson: Formulas for Ionic Compounds-The Crossover Rule Chemistry Lesson: Formulas for Ionic Compounds-The Crossover Rule

12. WRITING FORMULAS l Do the oxidation #’s = 0? –No; use criss-cross Exchange oxidation #’s but not the charges –ex. Al +3 + O 2- → Al 2 O 3 notice only the #’s crossed, not the charges

13. l The “criss-cross” method may help: l Step 1 Write the ions side by side: Fe +3 S -2 l Step 2 Draw arrows that cross each other: Fe +3 S -2 l Step 3 Put the number of charges at the ends: Fe +3 S -2 2 3

14. l Step 4 Write the formula as follows: a) write the positive ion without its charge: Fe b) write the number as a subscript (don’t write a 1):Fe 2 c) write the negative ion without its charge: Fe 2 S d) write the number as a subscript (don’t write a 1):Fe 2 S 3 e) … all done!

15. l Watch out for polyatomic compound ions (which contain more than one element), e.g. ammonium, hydroxide, nitrate, sulfate and carbonate. l If you need more than one of them to balance the charges, put brackets around their symbol at step (a) or (c). l For example, sodium hydroxide is NaOH, but magnesium hydroxide is Mg(OH) 2 ; and copper(II) sulfate is CuSO 4, but ammonium sulfate is (NH 4 ) 2 SO 4.

16. Video l Watch Tyler Dewitt demonstrate how to write formulas with polyatomic ions. l Writing Formulas with Polyatomic Ions Writing Formulas with Polyatomic Ions

17. Writing Ionic Compound Formulas Example: Barium nitrate (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Ba 2+ NO 3 - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance subscripts. Not balanced! ( ) 2 Now balanced. = Ba(NO 3 ) 2

18. Writing Ionic Compound Formulas Example: Ammonium sulfate (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! NH 4 + SO 4 2- 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts. Not balanced! ( ) 2 Now balanced. = (NH 4 ) 2 SO 4

19. Writing Ionic Compound Formulas Example: Iron (III) chloride (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Fe 3+ Cl - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts. Not balanced! 3 Now balanced. = FeCl 3

20. Writing Ionic Compound Formulas Example: Aluminum sulfide (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ S 2- 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts. Not balanced! 23 Now balanced. = Al 2 S 3

21. Writing Ionic Compound Formulas Example: Magnesium carbonate (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Mg 2+ CO 3 2- 2. Check to see if charges are balanced. They are balanced! = MgCO 3

22. Writing Ionic Compound Formulas Example: Zinc hydroxide (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Zn 2+ OH - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Use the criss-cross method to balance the subscripts. Not balanced! ( ) 2 Now balanced. = Zn(OH) 2

23. Writing Ionic Compound Formulas Example: Aluminum phosphate (note the 2 word name) 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ PO 4 3- 2. Check to see if charges are balanced. They ARE balanced! = AlPO 4

24. Write the formula Name Aluminum Nitrate Balanced Ion PairsFormula

25. Write the formula Name Aluminum Nitrate Balanced Ion PairsFormula Al +3 + 3NO 3 -

26. Write the formula Name Aluminum Nitrate Balanced Ion PairsFormula Al +3 + 3NO 3 - Al(NO 3 ) 3

27. Name the compound ElementsBalanced Ion Pairs FormulaName Li + N 3Li + + N -3 Li 3 N Lithium Nitride Mg + Cl Mg +2 + 2Cl - MgCl 2 Magnesium Chloride Rb + S 2Rb + + S 2- Rb 2 S Rubidium Sulfide

28. More Practice with Ionic Naming ElementsBalanced Ion Pairs FormulaName Al + O Ca + P Ga + F

29. Write balanced ion pairs ElementsBalanced Ion Pairs FormulaName Al + O 2Al +3 + 3O -2 Ca + P 3Ca +2 + 2P -3 Ga + F Ga +3 + 3F -

30. Write the formula ElementsBalanced Ion Pairs FormulaName Al + O 2Al +3 + 3O -2 Al 2 O 3 Ca + P 3Ca +2 + 2P -3 Ca 3 P 2 Ga + F Ga +3 + 3F - GaF 3

31. Name the compound ElementsBalanced Ion Pairs FormulaName Al + O 2Al +3 + 3O -2 Al 2 O 3 Aluminum Oxide Ca + P 3Ca +2 + 2P -3 Ca 3 P 2 Calcium Phosphide Ga + F Ga +3 + 3F - GaF 3 Galium Flouride

32. Naming with Polyatomic Ions IonsBalanced Ion Pairs FormulaName Na +1 + PO 4 -3 Ba +2 + PO 3 -3

33. Write Balanced Ion Pairs IonsBalanced Ion Pairs FormulaName Na +1 + PO 4 -3 3 Na +1 + PO 4 -3 Ba +2 + PO 3 -3 3Ba +2 + 2PO 3 -3

34. Write the formula IonsBalanced Ion Pairs FormulaName Na +1 + PO 4 -3 3 Na +1 + PO 4 -3 Na 3 PO 4 Ba +2 + PO 3 -3 3Ba +2 + 2PO 3 -3 Ba 3 (PO 3 ) 2

35. Name the compound IonsBalanced Ion Pairs FormulaName Na +1 + PO 4 -3 3 Na +1 + PO 4 -3 Na 3 PO 4 Sodium Phosphate Ba +2 + PO 3 -3 3Ba +2 + 2PO 3 -3 Ba 3 (PO 3 ) 2 Barium Phosphite

36. The student will: SWBAT’2  classify the type of bond that forms between two given elements.  write the chemical symbol/name given the name/chemical symbol of an element.  classify a given compound as ionic or molecular.  given a sheet of common ions, represent an ionic compound in multiple ways--using words and chemical formula.  represent a molecular compound in multiple ways-- using words, chemical formula and diagrams.  represent the seven common diatomic molecules in multiple ways-- using words, chemical formula and diagrams.

37. l 4: Same as a 3.0 but I can make inferences & application to the SWBAT’s l 3: I COMPLETELY understand all parts of the SWBAT l 2: I understand MOST of the SWBAT’s with teacher help l 1:I understand a little of the SWBAT’s but need teacher help l 0:I do NOT understand any part of the SWBAT’s and need help!