Section 9-4Section 9.4 Molecular Shapes

Summarize the VSEPR bonding theory.

atomic orbital: the region around an atom’s nucleus that defines an electron’s probable location

VSEPR modelhybridization

Predict the shape of, and the bond angles in, a molecule.

Define hybridization.

The VSEPR model is used to determine molecular shape.

Write a paragraph that includes all of the terms above.

Section 9-4VSEPR Model

The shape of a molecule determines many of its physical and chemical properties.

Molecular geometry (shape) can be determined with the Valence Shell Electron Pair Repulsion model, or VSEPR model which minimizes the repulsion of shared and unshared atoms around the central atom.

Electron pairs repel each other and cause molecules to be in fixed positions relative to each other.

Unshared electron pairs also determine the shape of a molecule.

Electron pairs are located in a molecule as far apart as they can be.

Hybridization is a process in which atomic orbitals mix and form new, identical hybrid orbitals.

Carbon often undergoes hybridization, which forms an sp3 orbital formed from one s orbital and three p orbitals. Lone pairs also occupy hybrid orbitals.

Single, double, and triple bonds occupy only one hybrid orbital (CO2 with two double bonds forms an sp hybrid orbital).

Section 9-4Hybridization (cont.)

Section 9-4Hybridization (cont.)

Section 9-4Hybridization (cont.)

Section 9.4

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Electronegativity and PolarityStandard: 2f, 259Mastering Concepts: 272(80-83)Terms: 259 Practice Problems: 262 (49-53)

Cornell Notes: 9.4Section Assessment: 262(54-57) Labs: 261Mastering Problems: 272(105-107)

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Mastering Concepts: 272(80-83)

80. On what is the VSEPR model based? (9.4)

the repulsive nature of electron pairs around a central atom

Mastering Concepts: 272(80-83)

81. What is the molecular shape of each of the following molecules? Estimate the bond angle for each assuming no lone pair. (9.4)a. A—B

linear, 180°

b. A—B—A

linear, 180°

Mastering Concepts: 272(80-83)

c. A—B—A A

trigonal planar, 120°

Mastering Concepts: 272(80-83)

d. A A—B—A A

tetrahedral, 109°

Mastering Concepts: 272(80-83)

82. What is the maximum number of hybrid orbitals a carbon atom can form? (9.4)

four

Mastering Concepts: 272(80-83)

• 83. Explain the theory of hybridization and determine the number of hybrid orbitals present in the molecule PCl5. (9.4)

five identical sp3d orbitals formed

Building VSEPR Lab 261

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Electronegativity and PolarityStandard: 2f, 259Mastering Concepts: 272(80-83)Terms: 259 Practice Problems: 262 (49-53)

Cornell Notes: 9.4Section Assessment: 262(54-57) Labs: 261Mastering Problems: 272(105-107)

19

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

49. BF3

50. NH4+

51. OCl2

52. BeF2

53. CF4

20

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

49. BF3

1s 2s 2p

21

Mix and create new

trigonal planar, 120°, sp21s sp

Max the # unpaired electrons available for bonding

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

50. NH4+

1s 2s 2p

22

Mix and create new

tetrahedral, 109°, sp31s sp

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

51. OCl2

1s 2s 2p

23

Mix and create new

bent, 104.5°, sp31s sp

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

52. BeF2

1s 2s 2p

24

Mix and create new

linear, 180°, sp1s sp

Practice Problems: 262 (49-53)

Determine the molecular geometry, bond angle, and type of hybridization for the following.

53. CF4

1s 2s 2p

25

Mix and create new

tetrahedral, 109°, sp31s sp