1. Catalyst – October 6(4), 2012 WAY BACK WEDNESDAY!
What is the mass of an atom that has 14 protons and 15 neutrons?
The reaction of baking soda and vinegar at 25 degrees Celsius produces gaseous carbon dioxide for 1 minute. Which of the following do you think will happen if you react baking soda and vinegar at 50 degrees Celsius?
a) Less gas will be produced
b) Gas will be produced for more than 1 minute
c) The reaction will have a strong odor
d) The reaction will not occur

2. Today’s Agenda Catalyst
Electronegativity Difference, Bond Type, and Bond Polarity
Work Time
Speed Dating???
Exit Question
HW: Study for Test!

3. Today’s Objectives
SWBAT determine bond type using electronegativity differences (∆EN).
SWBAT classify compounds as ionic or covalent, describe characteristics, and write names and formulas correctly.
SWBAT get ready to DOMINATE the Test tomorrow!!!!

4. NOTES TITLE: ELECTRONEGATIVITY DIFFERENCE AND BOND TYPE

5. How to tell ionic and covalent apart
Key Point #1: Along with looking at the formula and name for a compound, we can also look at electronegativity differences (∆EN) in order to determine bond type (ionic or covalent).

6. Electronegativity Differences
We can also look at electronegativity differences (∆EN)
Look at Electronegativity Chart to find element electronegativities
Find the difference by using subtraction
Look at Bond Type Chart to determine bond types
Electronegativity Chart

7. Remember…
Electronegativity is an atom’s ability to attract electrons to itself in a chemical bond
Electronegativity is expressed in numerical values of 4.0 or less
These numerical values are called Paulings
Higher number means the atom will attract electrons more strongly

8. Electronegativity Chart
Pauling Values

9. Bond Polarity
Key Point #2: Bond polarity is based on differences in electronegativities of atoms forming a bond.
As electronegativity difference (∆EN) increases, polarity of bond increases

10. Bond Polarity Terms to Know
Pure Ionic = Complete transfer of electrons from one atom to another
Polar Covalent = Unequal sharing of electrons between two atoms
Nonpolar Covalent = Equal sharing of electrons between two atoms

11. Pure Ionic Bonding I have no chance!
Total give and take (transfer) of electrons! = Big ∆EN!
I have no chance!

12. Covalent Bonding is like a Tug-of-War
The more electronegative atom will pull electrons harder

13. Polarity and Electronegativity
Polar Covalent - electrons are pulled more toward one of the atoms
Big ∆EN!
Nonpolar Covalent - electrons are shared equally between atoms
Low ∆EN!
Big Dog – Little Dog
Medium Dog – Medium Dog

14. Polarity Ranges
Key Point #3: Bonds are not always purely ionic (I) or purely covalent (NPC). They could be slightly ionic (VPC) or slightly covalent (MPC).

17. How to Calculate Electronegativity Difference (∆EN)
1. Using Electronegativity Chart, find Pauling values for each element
2. Subtract the smaller number from the bigger number
Example: 4.0 (F) – 0.9 (Na) = 3.1
3. Look at Bond Type Chart to determine bond polarity

18. Bond Type Chart – Copy into notes!
∆EN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic

19. Example 1 Determine the type of bond in LiBr
Find electronegativity of each atom

20. Electronegativity Chart

21. Example 1 Determine the type of bond in LiBr
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings

22. Example 1 Determine the type of bond in LiBr
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings
Find Electronegativity Difference (∆EN)
DEN = 3.0 – 1.0 = 2.0
Look at chart to determine bond type.

23. Moderately Polar Covalent
Bond Type Chart
DEN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic

24. Example 1 Determine the type of bond in LiBr
Find electronegativity of each atom
Li = 1.0 Paulings, Br = 3.0 Paulings
Find Electronegativity Difference (∆EN)
DEN = 3.0 – 1.0 = 2.0
Look at chart to determine bond type.
Bond Type: Ionic

25. Example 2 Determine the type of bond in O2
Find electronegativity of each atom

26. Electronegativity Chart

27. Example 2 Determine the type of bond in O2
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings

28. Example 2 Determine the type of bond in O2
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings
Find Electronegativity Difference (∆EN)
DEN = 3.4 – 3.4 = 0
Look at chart to determine bond type.

29. Moderately Polar Covalent
Bond Type Chart
DEN Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic

30. Example 2 Determine the type of bond in O2
Find electronegativity of each atom
O = 3.4 Paulings, O = 3.4 Paulings
Find Electronegativity Difference (∆EN)
DEN = 3.4 – 3.4 = 0
Look at chart to determine bond type.
Bond Type: Nonpolar Covalent

31. CO 4. HF AlP 5. CaO N2 6. H2 How Polar Is It?
Determine the polarity of each bond in the following compounds by calculating the electronegativity difference for each:
CO HF
AlP CaO
N H2

32. Electronegativity Chart

33. Moderately Polar Covalent
Bond Type Chart
Range
Bond Type
0.0 – 0.39
Nonpolar Covalent
0.4 – 0.89
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic

34. Practice Time!
Please finish the worksheet

35. Exit Question
Write one thing you will do today/tonight to get ready to DOMINATE the Test tomorrow.
Then doooo it!

36. Exit Question Magnesium is a metal. Sulfur is a nonmetal.
What type of bond is formed between these elements?
Describe two ways that you could use to determine your answer to number 1.
HW: Review Chapter 12,
Review Sheet, STUDY!

37. Catalyst – September 23+6, 2011 What is a cation?
What bond shares electrons?
Complete the analogy:
Opposite is to ionic as __________ is to covalent.

38. HW: Unit 3 Practice Test Questions (Half-Sheet)
Today’s Agenda
Catalyst
Project Work Time
Speed Dating
Exit Question
HW: Unit 3 Practice Test Questions (Half-Sheet)

39. Today’s Objectives
SWBAT complete AWESOME Chemistry.com Projects.
SWBAT find love in Speed Dating!

40. Speed Dating Half of you will remain STATIONARY
Half of you will rotate IN ORDER, CLOCKWISE
You will have 4 minutes with each “date”
Ask each other questions to determine if your atoms have a potential love match!

41. Exit Question

42. Catalyst – September 5(6), 2011 FUN GRAPH FRIDAY!
What are TWO questions you could ask when looking at this graph?

43. Today’s Agenda Catalyst HW Review Ionic vs. Covalent Lab!
Do Gatorade or Powerade Conduct Electricity?
Group of the Week
Exit Question

44. Today’s Objectives
SWBAT conduct an experiment to determine if unknown substances are ionic or covalent.

45. Today’s Lab Safety: Be careful with hotplates. Be Goggle Gangsters!
Alternate between heating and conductivity tests

46. Unknown Substances
A: Salol
B: Sodium Chloride (Salt)
C: Copper (II) Sulfate
D: Sucrose (Sugar)

47. Salol Chemical Name: Phenyl salicylate Chemical Formula: C13H10O3
Melting Point: 41.5˚C

48. Sodium Chloride (Salt)
Chemical Name: Sodium Chloride
Chemical Formula: NaCl
Melting Point: 861˚C

49. Copper (II) Sulfate Chemical Name: Copper (II) Sulfate
Chemical Formula: CuSO4
Melting Point: 110˚C

50. Sucrose (Sugar) Chemical Name: Copper (II) Sulfate
Chemical Formula: C12H22O11
Melting Point: 186˚C

51. Exit Question
We have just officially entered the Fall season. What is your favorite season and why?

52. Monday Mystery Element!
Catalyst – October 22-1, 2011
Monday Mystery Element!
Element’s Greek name means “moon”
Added to dandruff shampoos
Protects against cancer

53. Monday Mystery Element!
Catalyst – October 22-1, 2011
Monday Mystery Element!
Element’s Greek name means “moon”
Added to dandruff shampoos
Protects against cancer
SELENIUM!

54. HW: STUDYYYYYYY FOR THE TEST TOMORROW!!!!
Today’s Agenda
Catalyst (New Groups after test)
Gatorade/Powerade Test
Unit 3 Test Review with Ms. Stroh
Work Time
Exit Question
HW: STUDYYYYYYY FOR THE TEST TOMORROW!!!!

55. SWBAT get ready to DOMINATE tomorrow’s Unit 3 Test!
Today’s Agenda
SWBAT get ready to DOMINATE tomorrow’s Unit 3 Test!

56. Unit 3– What You Need to Know…
Ionic, Covalent, Metallic Similarities and Differences
Characteristics of Ionic and Covalent
Octet Rule
Lewis Dot Structures for Ions and Compounds
Ionic Formulas and Names
Kriss-Kross, No Prefixes, Transition Metals, Polyatomic Ions
Covalent Formulas and Names
No Kriss-Krossing, Formula Subscripts = Name Prefixes
Determining Bond Type with Electronegativity Difference

57. Get to Know Your Compounds
Partner up with someone in your group
Ask each other, “If you were a chemical compound, would you want to be ionic or covalent and why?”
Be ready to share each other’s answer

58. Octet Rule
While bonding, atoms will give, take, and/or share electrons in order to have a full valence (outer) shell (2 or 8 electrons)

59. Lewis Dot Structures Draw the LDS for the following atoms and ions…
Mg, S, Br, Al, O2-, K1+ , C4+
Model the ionic bond formation for…
Lithium chloride
Draw the LDS for the covalent compounds…
SiF4, H2S, CO, SO

60. REVIEW OF
NAMING &
FORMULAS!

61. Yo Yo! Let’s break it down!
IONIC
Metal + Nonmetal
Writing Formulas:
Kriss Kross charges
Naming:
2nd element ends in – ide, ignore subscripts
COVALENT
Nonmetal + Nonmetal
Writing Formulas:
Prefixes = subscript #s
Naming:
2nd element ends in –ide, don’t ignore subscripts – use prefixes

62. How do we know if our compound is ionic or covalent?
Is it between a metal and a non-metal?
YES!!! Then, it is ionic!!!
Is it between a non-metal and a non- metal?
Then, it is covalent!

63. Ionic Bond
Metal Cation: Li
Nonmetal Anion: O
Li O

64. Ionic Bond
Metal Cation: Li
Nonmetal Anion: O
Li1+ O2-

65. Ionic Bond
Metal Cation: Li
Nonmetal Anion: O
Li1+ O2-

66. Ionic Bond
Metal Cation: Li
Nonmetal Anion: O
Li2O

67. MgO

68. MgO
Magnesium Oxide

69. NBr3

70. NBr3
Nitrogen tribromide

71. Write the names and formulas… First! Decide if it’s ionic or covalent!
Write names
Na2O
CO2
CaBr
Na2CO3
Mg3P2
K2S
N2S3
Write formulas
Carbon monoxide
Barium nitrate
Xenon difluoride
Carbon tetrachloride
Sodium carbonate
Lithium fluoride
Nitrogen trifluoride

72. CO 4. HF AlP 5. CaO N2 6. H2 How Polar Is It?
Determine the polarity of each bond in the following compounds by calculating the electronegativity difference for each:
CO HF
AlP CaO
N H2

73. Polarity and Electronegativity
Polar Covalent - electrons are pulled more toward one of the atoms
Big ∆EN!
Nonpolar Covalent - electrons are shared equally between atoms
Low ∆EN!
Big Dog – Little Dog
Medium Dog – Medium Dog

74. Polarity Ranges
Bonds are not always purely ionic (I) or purely covalent (NPC). They could be slightly ionic (VPC) or slightly covalent (MPC).

75. Electronegativity Chart

76. Moderately Polar Covalent
Bond Type Chart
Range
Bond Type
0.0 – 0.3
Nonpolar Covalent
0.4 – 0.9
Moderately Polar Covalent
0.9 – 1.69
Very Polar Covalent
1.7 or greater
Ionic

77. Unit 3 Review Work Time Your Options: Not Your Option Review Sheet
Extra Worksheets provided by Ms. Stroh
Read book
Not Your Option
Wasting time and being unproductive

78. Exit Question What grade are you shooting for on this test?
What do you plan to actually do today/tonight in order to prepare for the test?
(Some options: study on your own, study with a friend, complete review sheet, read book, come at lunch or after school for tutoring, etc.)