1. 3 January 2012 Take Out Bonding Problem Set
Objective: You will be able to:
describe the VSEPR model and describe molecular geometry for 2 to 4 electron domains
Do now: On your white paper, across the top of a long edge, draw the Lewis structures for:
carbon dioxide
boron trifluoride
methane
ammonia

2. Agenda Homework Quiz Collect Winter Break Homework
We’ll do a review of intermolecular forces after this current (short) unit
VSEPR Theory and Molecular Geometry
Homework: p. 453 #1, 2, 7, 9, 12 (please sketch neatly!): tomorrow
I’ll collect the Intermolecular Forces problem set tomorrow. See me after school with questions!

3. Keys?

4. The VSEPR Model
Valence-shell electron-pair repulsion (VSEPR) model: a way to use Lewis structures to determine the geometries (shapes) of molecules.
based on repulsive forces that exist between electron pairs within molecules
geometry: the arrangement of a molecule’s atoms in three-dimensional space

5. bond angle: an angle made by the lines joining the nuclei of atoms in a molecule
electron domain: a region around an atom in which electrons will most likely be found.
produced by a non-bonding pair, a single bond, a double bond or a triple bond

6. Activity
On your white paper, across the top of a long edge, draw the Lewis structures for:
carbon dioxide
boron trifluoride
methane
ammonia
Then, with your knowledge of the VSEPR theory, construct models for each molecule that predict it’s 3D geometry. Sketch these below each Lewis structure.
Measure and label the bond angles.

8. Linear 2 bonding domains 0 non-bonding domains 180o

9. Trigonal Planar 3 bonding domains 0 non-bonding domains 120o

10. Non-linear (bent) 2 bonding domains 1 non-bonding domain 117o

11. Tetrahedral 4 bonding domains 0 non-bonding domains 109.5o

12. Trigonal pyramidal 3 bonding domains 1 non-bonding domain 107o

13. Non-linear (bent) 2 bonding domains 2 non-bonding domains 104o

14. On your paper
Label the shapes of the four molecules you already constructed
Draw Lewis structures for
NO2-
H2O
Determine their shape. Build the model.
Draw a sketch, label the shape name and the bond angle.

15. Next Up
What about molecules with 5 or 6 electron domains?!

16. Homework
p. 453 #1, 2, 7, 9, 12: tomorrow

17. 4 January 2012 Take Out: Problem sets, p. 453 Homework
Objective: You will be able to:
use VSEPR theory to determine the shapes of molecules with five and six electron domains around the central atom.
Homework Quiz: Draw the Lewis structure, determine the shape, sketch, label the bond angle: HCF3
Bonus: Describe the polarity of this molecule.

18. Agenda Homework Quiz Homework Answers
Shapes of molecules with five and six electron domains: Notes
Polarity?
Homework: p. 453 #7d, 8, 10, 12d, e, g, 13, 14: Mon.
read p , ignore equations: Mon.

19. Draw Lewis Structures for…
PCl5
SF4
ClF3
XeF2

20. Electron-Domain Geometry
Trigonal bipyramidal: 5 electron domains
trigonal bipyramidal (5 bonding, 0 non)
seesaw (4, 1)
T-shaped (3, 2)
Linear (2, 3)

21. Draw Lewis Structures for…
BrF5
XeF4

22. Electron-Domain Geometry
Octahedral: 6 electron domains
octahedral (6 bonding, 0 non)
square pyramidal (5, 1)
square planar (4, 2)

23. 9 January 2012 Take Out Homework Objective: You will be able to:
identify and describe the polarity of bonds and molecules
Homework Quiz: a. Draw a Lewis Structure b. Identify the shape c. Sketch
a. IBr3 b. SI6

24. Agenda Homework Quiz Homework Answers
Polarity Notes and Practice Problems
Hand back assignments
Homework: p. 454 #18, 20, 23
finish polarity practice problems
read p

25. Practice Problems
Draw Lewis Structures, predict geometry (electron domain and molecular), sketch, label:
PBr5
SI6
ClF4+
SF5-
BCl3
IBr3
XeCl2

26. Polarity
bond polarity: a measure of how equally the electrons in a bond are shared between two atoms.
the greater the difference in electronegativity of the bonded atoms, the more polar the bond.

27. dipole moment: measure of the charge separation in a molecule; how polar the entire molecule is
the vector sum of all the bond dipoles

28. Examples
HCl
BF3
CCl4
NH3
CH3Cl

29. Examples
C2H2Cl2

30. Practice Problems 1. SO2 9. BF3 2. CCl4 10. SF3+ 3. CHCl3 11. XeF2
4. TeCl BrF5
5. CO XeF4
6. NH SeF4
7. SO ClF3
8. CO SeF6

31. Homework p. 454 #18, 20, 23 finish polarity practice problems
read p

32. 10 January 2012 Take Out Homework Objective: You will be able to:
describe and identify hybridization of orbitals in molecules and describe and count sigma and pi bonds.
Homework Quiz: SF3+ a. Draw the shape and label with the shape name. b. Indicate bond moments. c. Indicate dipole moment, if any. d. Polar or non polar?

33. Agenda Homework Quiz Hybridization Notes and Practice Problems
Sigma and Pi Bond Notes and Practice Problems
Homework: p. 454 #31, 32, 34, 35, 37, 39, 40, 41, 42, 69, 71, 75, 82, 99 b0nus: 100: Thurs.

34. Hybridization

35. VSEPR Theory Review Valence electrons only are involved in bonding.
Non-bonding and bonding electron pairs around the central atom repel each other.
This repulsion causes specific shapes and bond angles for each molecule.

36. Question
How can atoms, that have s, p and d orbitals, bond in ways that make the molecule shapes?
Ex: p orbitals at 90o angles to each other.
How can they make a bond angle of 109.5o in tetrahedral or 120o in trigonal planar?? ?

37. Energy
1s 2s p s
Carbon Hydrogen
How can carbon make four bonds with four hydrogen atoms?? How can those bonds be at 109.5o (tetrahedral)?

38. Answer: Hybrid orbitals: the sublevels in an atom’s outer shell recombine into new orbitals of equal energy with different shapes and angles.
Energy
1s sp3 hybrid orbital
Hybridization: the mixing of atomic orbitals in an atom (usually the central atom) to generate a set of hybrid orbitals.

39. Total energy the same, but redistributed
1s 2s p s
Carbon Hydrogen
Energy
1s sp3 hybrid orbital
Total energy the same, but redistributed 39

40. Animation http://www.youtube.com/watch?v=g1fGX DRxS6k
/essentialchemistry/flash/hybrv18.swf

41. sp3 Example
CH4

43. sp hybridization
BeCl2

44. 12 January 2012 Objective: You will be able to:
describe and identify hybridization of orbitals in molecules and describe and count sigma and pi bonds.
review bonding and molecular geometry.

45. Agenda Hybridization notes Practice problems
Sigma and pi bond notes and examples
Problem Set work time
Homework: p. 454 #31, 32, 34, 35, 37, 39, 40, 41, 42, 69, 71, 75, 82, 99 b0nus: 100: Tues.
Problem Set: Tues
Test Weds.

46. sp2 hybridization
BF3

47. Shapes of hybrid orbitals
s, p
s, p, p
trigonal pyramidal
s, p, p, p

48. NH3 is also sp3 hybridization: three orbitals for the H, one orbital for the non-bonding pair.

49. Steps to Determine Hybridization
Draw the Lewis structure
Predict the molecule shape using the VSEPR theory
Determine hybridization by matching the arrangement of the molecule with known examples (table 10.4)

50. For each compound’s central atom, draw the orbital notation.
Then, draw the orbital notation after hybridization.
Name the type of hybridization and the shape of each molecule.
BeH2
AlI3
PF3
SiF4
CO2
PH3
H2O

51. Multiple Bonds

52. When a double bond forms, the two bonds are not exactly the same.
First: “end on” s-orbital interaction: σ (sigma) bonds
Second: “side on” p-orbital interaction: π (pi) bonds

53. Single bonds: always σ bonds.
Double bonds: one σ + one π bond.
Triple bonds: one σ bond +two π bonds

54. Count sigma and pi bonds
CHCl3
SCO
SeO2
ClO3-

55. Practice Problems
Count the total number of sigma and pi bonds in each molecule
Draw a Lewis structure first!
H2CO O2
CO2
HCN (C is the central atom)
CSN- (C is the central atom)
N3-

56. Homework
p. 454 #31, 32, 34, 35, 37, 39, 40, 41, 42, 69, 71, 74, 75, 82, 99 b0nus: 100: Thurs.

57. 17 January 2012 Objective: You will be able to:
review chemical bonding and molecular geometry for a test.
Homework Quiz: For the molecule on the board:
Describe/label bond moments and dipole moment, if any.
Describe the hybridization around each C atom
How many sigma bonds? Pi?

58. Agenda Homework quiz Questions on problem set/homework?
Collect problem set
Midterm Review
Homework: Unit 6 test tomorrow

59. Unit 6 Test
12 multiple choice
1 four-part free response
1 period!!

60. Midterm Exam 26 multiple choice, no calc.
2 predict products/write equation
2 multi-part free response, with calc.
110 minutes

61. Textbook Homework
Questions?

62. Problem Set
Questions?

63. Homework
Study for Unit Test
Midterm Review starts Thursday