1. Your Turn!
A central atom has two lone pair of electrons around it and two single bonds to other atoms. What is the electron pair geometry around the central atom?
tetrahedron
pentagon
trigonal bipyramid
square pyramid
octahedron

2. Your Turn!
What is the electron pair geometry around an atom that has six electron domains?
What are the angles between the electron pairs?
tetrahedron, 109.5o
hexagon, 60o and 120o
trigonal bipyramid, 120o
square pyramid, 90o
octahedron, 90o or

3. Predict electronic and molecular shapes
Use the tables in your text or on the next two slides
AsF3 tetrahedral, trigonal pyramidal
ClO2- tetrahedral, bent
ClF trigonal bipyramidal, T-shaped

6. Your Turn!
What is the molecular geometry of a molecule with four single bonds and two lone electron pairs attached to the center atom?
A. trigonal bipyramid
B. trigonal planar
C. distorted tetrahedron
D. square pyramid
E. square planar

7. PCl3 is an industrial chemical used in many herbicides and insecticides. What is the molecular shape of PCl3?
bent
tetrahedral
trigonal pyramidal
T-shaped
trigonal planar

8. Predict the geometry and bond angles of PCl3
1. Draw the Lewis structure
- 26 valence electrons
2. Determine the number of electron domains around the central atom
- four electron domains around P

9. Predict the geometry and bond angles of PCl3
3. Classify the electron domains
a) three bonding groups
b) one lone pair
4. Use Table 9.5 to determine the shape and bond angles
a) four electron domains around P = tetrahedral electron geometry
b) three bonding + one lone pair = trigonal pyramidal molecular geometry
c) trigonal pyramidal = bond angles less than 109.5°

10. PCl3 is an industrial chemical used in many herbicides and insecticides. What is the molecular shape of PCl3?
bent
tetrahedral
trigonal pyramidal
T-shaped
trigonal planar
Answer: c

11. What are the electron and molecular geometries, respectively, for BrF3?
trigonal bipyramidal, T-shaped
trigonal bipyramidal, trigonal planar
trigonal planar, trigonal planar
T-shaped, trigonal bipyramidal
T-shaped, trigonal planar

12. What are the electron and molecular geometries, respectively, for BrF3?
trigonal bipyramidal, T-shaped
trigonal bipyramidal, trigonal planar
trigonal planar, trigonal planar
T-shaped, trigonal bipyramidal
T-shaped, trigonal planar
Answer: a

13. Predict the molecular geometry and bond angles in SiF5─
Si least electronegative
5 electron groups on Si
Si is central atom
5 bonding groups
0 lone pairs
Si = 4e─
F5 = 5(7e─) = 35e─
(─) = 1e─
total = 40e─
Shape = trigonal bipyramid
Bond angles
Feq–Si–Feq = 120°
Feq–Si–Fax = 90°

14. Your Turn!
How many electron domains are there around the central atom in SF4O? What is the electron pair geometry for the compound?
4, tetrahedron
5, pentagon
5, trigonal bipyramid
4, square pyramid
6, octahedron

15. Your Turn!
For the species, ICl5, how many bonding domains and how many nonbonding domains exist?
A. 1, 5
B. 4, 1
C. 1, 4
D. 5, 2
E. 5, 1

16. Your Turn!
For the species that you just considered, ICl5, what is the electron domain geometry? A. trigonal planar B. tetrahedron C. trigonal bipyramid D. octahedron

17. Your Turn!
For the species that you just considered, ICl5, what is the molecular geometry? A. trigonal bipyramid B. trigonal planar C. distorted tetrahedron D. square pyramid

18. Predict whether NH3 is a polar molecule
Draw the Lewis structure and determine the molecular geometry
a) eight valence electrons
b) three bonding + one lone pair = trigonal pyramidal molecular geometry

19. Predict whether NH3 is a polar molecule
2. Determine if the bonds are polar
a) electronegativity difference
b) if the bonds are not polar, we can stop here and declare the molecule will be nonpolar
ENN = 3.0
ENH = 2.1
3.0 − 2.1 = 0.9
therefore the bonds are polar covalent

20. Predict whether NH3 is a polar molecule
3) Determine whether the polar bonds add together to give a net dipole moment
a) vector addition
b) generally, asymmetric shapes result in uncompensated polarities and a net dipole moment
The H─N bond is polar. All the sets of bonding electrons are pulled toward the N end of the molecule. The net result is a polar molecule.

21. Practice – Decide whether the following molecules are polar.
Trigonal
Bent
Trigonal
Planar
2.5
1. polar bonds, N-O
2. asymmetrical shape
1. polar bonds, all S-O
2. Polar bonds cancel out
polar
nonpolar

22. Which of the following molecules is the most polar molecule?
a) b) c) d) e)

23. Which of the following molecules is the most polar molecule?
a) b) c) d) e)
Answer: c

24. Which of the following molecules is nonpolar?
NH3
XeF4
H2O
CH3Cl
CH2Cl2

25. Which of the following molecules is nonpolar?
NH3
XeF4
H2O
CH3Cl
CH2Cl2
Answer: b

26. Your Turn!
Imagine a molecule, MX2, in which both X atoms are bonded to M and M also has 3 lone electron pairs on it. What is the electron domain geometry and is this molecule polar?
A. square pyramidal, yes
B. trigonal bipyramidal, no
C. tetrahedral, yes
D. tetrahedral, no
E. linear, no

27. Your Turn!
Imagine a molecule, MX2, in which both X atoms are bonded to M and M also has 2 lone electron pairs on it. What is the electron domain geometry and is this molecule polar?
A. square pyramidal, yes
B. trigonal bipyramidal, no
C. tetrahedral, yes
D. tetrahedral, no
E. linear, no
H2O is an example:

28. Your Turn! Which of the following molecules is polar? A. BClF2 B. BF3
C. NH4+
D. NO3–
E. C2H2

29. Your Turn!
On the previous slide we saw that hybridizing s + p + p forms three hybrid orbitals designated as sp 2 orbitals. Predict the number and designation of orbitals formed by hybridizing s + p + p + p + d (i.e., hybridize one s, three p, and one d orbital).
A. three, spd
B. three, sp3d
C. five, spd
D. five, sp3d
E. five, s3pd 29

30. Your Turn!
What is the hybridization of oxygen in OCl2? A. sp B. sp 3 C. sp 2 D. No hybridization

31. Two electron domains and 180o bond angle: sp hybrid orbitals
Your Turn!
What is the hybridization of the carbon atom in carbon disulfide?
A. sp
B. sp 3
C. sp 2
D. sp 3d
D. sp 3d 2 C S
Two electron domains and
180o bond angle: sp hybrid orbitals

32. Your Turn! For the species ClF2+, determine the following:
1. electron domain geometry
molecular geometry
tetrahedral, trigonal planar
pentagonal, tetrahedral
tetrahedral, bent
trigonal planar, bent

33. Your Turn!
For the species ClF2+, determine the following: 1. hybridization around the central atom 2. Polarity A. sp 2, polar B. sp 3, non-polar C. sp 3, polar D. sp 2, non-polar

34. Your Turn! For the species XeF4O, determine the following:
1. electron domain geometry
2. molecular geometry
octahedral, square pyramidal
trigonal bipyramidal, distorted tetrahedral
square pyramidal, octahedral
trigonal bipyramidal, planar

35. Your Turn! For the species XeF4O, determine the following:
hybridization around the central atom
the molecular polarity
A. sp3d , polar
B. sp3d 2, polar
C. sp3d , nonpolar
D. sp3d2, nonpolar

36. Your Turn!
How many  and  bonds are there in CH2CHCHCH2, and what is the hybridization around the carbon atoms?
A. 7, 1, sp
B. 8, 2, sp 3
C. 9, 2, sp 2
D. 9, 3, sp 2
E. 8, 2, sp

37. Your Turn!
How many  and  bonds are there in carbon monoxide and what is the hybridization of the C and O atoms? A. 1, 2, both sp B. 2, 2, both sp C. 0, 3, both sp 2 D. 3, 0, sp 2 and sp E. 3, 2, sp 2 and sp C O

38. Which orbitals overlap to form the σ bond between the sulfur and fluorine atoms in the molecule SF4?
sp3d hybrid of S and 2p of F
sp3 hybrid of S and 2p of F
sp2 hybrid of S and 3p of F
sp3d2 hybrid of S and 2p of F
sp3d hybrid of S and 3p of F

39. Which orbitals overlap to form the σ bond between the sulfur and fluorine atoms in the molecule SF4?
sp3d hybrid of S and 2p of F
sp3 hybrid of S and 2p of F
sp2 hybrid of S and 3p of F
sp3d2 hybrid of S and 2p of F
sp3d hybrid of S and 3p of F
Answer: a

40. What is the hybridization of the central atom in XeF2?sp
sp2
sp3
sp3d
sp3d2

41. What is the hybridization of the central atom in XeF2?sp
sp2
sp3
sp3d
sp3d2
Answer: d

42. If the electron pair geometry around an atom is tetrahedral, then the hybridization about that atom is
sp.
sp2.
sp3.
sp3d.
sp3d2.

43. If the electron pair geometry around an atom is tetrahedral, then the hybridization about that atom is
sp.
sp2.
sp3.
sp3d.
sp3d2.
Answer: c

44. Which of the following hybridization schemes allows the formation of at least one  bond?
sp3
sp2
sp3d2
All of the above allow for a  bond.
None of the above allow for a  bond.

45. Which of the following hybridization schemes allows the formation of at least one  bond?
sp3
sp2
sp3d2
All of the above allow for a  bond.
None of the above allow for a  bond.
Answer: b

46. Which molecule has the smallest bond angles?
CO2
NH3
SF6
BrF5

47. Which molecule has the smallest bond angles?
CO2
NH3
SF6
BrF5
Answer: d
Draw Lewis structures. BrF5 has a lone pair which compresses the octahedral bond angles.