1. Writing Formulas for Binary Ionic Compounds

2. The first thing we need is a couple of definitions:

3. 1.When a metal combines with a non- metal, an ionic compound is formed.

4. The first thing we need is a couple of definitions: 1.When a metal combines with a non- metal, an ionic compound is formed. 2.A binary compound consists of only two elements.

5. In Science 10, you’ll be given this Periodic Table:

7. See the staircase!

8. In Science 10, you’ll be given this Periodic Table: METALS

9. In Science 10, you’ll be given this Periodic Table: METALSNON-METALS

10. A binary ionic compound forms when:

11. A binary ionic compound forms when: a positively charged metal ion combines with

12. A binary ionic compound forms when: a positively charged metal ion combines with a negatively charged non-metal ion.

13. What the formula for an ionic compound means.

14. The formula for the ionic compound sodium chloride is NaCl.

15. This does NOT mean that sodium chloride consists of individual NaCl “molecules” like this:

16. The formula for the ionic compound sodium chloride is NaCl. This does NOT mean that sodium chloride consists of individual NaCl “molecules” like this: Na Cl

17. The formula for the ionic compound sodium chloride is NaCl. This does NOT mean that sodium chloride consists of individual NaCl “molecules” like this: Na Cl

18. Na + ion Cl – ion

19. Na + ion Cl – ion Crystal lattice of NaCl

20. For every Na + ion, there is one Cl – ion Na + ion Cl – ion

21. Na + ion Cl – ion formula smallest whole number ratio The formula for an ionic compound gives the smallest whole number ratio of ions.

22. For every Na + ion, there is one Cl – ion Na + ion Cl – ion formula The formula for sodium chloride is Na 1 Cl 1 = NaCl

23. For every Na + ion, there is one Cl – ion Na + ion Cl – ion The formula for sodium chloride is Na 1 Cl 1 = NaCl

24. The formula for calcium fluoride is CaF 2 This means that calcium fluoride consists of a huge pile of Ca 2+ and F – ions. CaF 2

25. The formula for calcium fluoride is CaF 2 This means that calcium fluoride consists of a huge pile of Ca 2+ and F – ions. CaF 2

26. The formula for calcium fluoride is CaF 2 This means that calcium fluoride consists of a huge pile of Ca 2+ and F – ions. CaF 2 For every Ca 2+ ion, there are 2 F – ions

27. Finding the formula for an ionic compound

28. There are two methods that we will show you for finding formulas.

29. There are two methods that we will show you for finding formulas. Then you can decide which method works best for you.

30. There are two methods that we will show you for finding formulas. Then you can decide which method works best for you. The two methods are:

31. 1.Equalizing + and – charges

32. There are two methods that we will show you for finding formulas. Then you can decide which method works best for you. The two methods are: 1.Equalizing + and – charges 2.Crossing down charges

33. Finding a formula by equalizing + and – charges

34. What is the formula for aluminum bromide?

35. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges Formula

36. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges Formula

37. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide?

38. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges Formula

39. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges +3–1 Formula

40. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges +3 Formula

41. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges +3–3 Formula

42. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges +3–3 Formula Add up to 0

43. Finding a formula by equalizing + and – charges What is the formula for aluminum bromide? Ion Namealuminumbromide Ions Al 3+ Br 1– Total Charges +3–3 Formula AlBr 3

44. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +2–3 Formula Ca 3 P 2

45. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +2–3 Formula Ca 3 P 2

46. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide?

47. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +2–3 Formula Ca 3 P 2

48. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +2–3 Formula Ca 3 P 2

49. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +6–6 Formula Ca 3 P 2

50. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +6–6 Formula Ca 3 P 2

51. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +6–6 Formula Ca 3 P 2

52. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +6–6 Formula Ca 3 P 2 Add up to 0

53. Finding a formula by equalizing + and – charges What is the formula for calcium phosphide? Ion Namecalciumphosphide Ions Ca 2+ P 3– Total Charges +6–6 Formula Ca 3 P 2

54. Finding a formula by crossing down charges

55. What is the formula for rubidium sulphide?

56. Finding a formula by crossing down charges What is the formula for rubidium sulphide?

57. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S

58. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S

59. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S

60. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S

61. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S

62. Finding a formula by crossing down charges What is the formula for rubidium sulphide? Rb 1+ S 2– Rb 2 S Formula

63. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide?

64. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide?

65. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? Mulitvalent metal

66. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? Mulitvalent metal

67. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? Tells us what the ion charge is

68. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide?

69. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

70. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

71. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

72. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

73. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

74. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4

75. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4 Both of these numbers are multiples of 2

76. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4 Divide both of these numbers by 2

77. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4 VO2VO2 ÷2

78. Finding a formula by crossing down charges What is the formula for vanadium(IV) oxide? V 4+ O 2– V2O4V2O4 VO2VO2 Formula