Transcript 9_4_Molecular Shapesx

Section 9.4 Molecular Shapes
Section 9-4
Summarize the VSEPR
bonding theory.
Predict the shape of, and the
bond angles in, a
molecule.
Define hybridization.
atomic orbital: the region
around an atom’s nucleus
that defines an electron’s
probable location
VSEPR model
hybridization
The VSEPR model is used to determine
molecular shape.
Write a paragraph that includes all of the
terms above.
VSEPR Model
Section 9-4
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).
Hybridization (cont.)
Section 9-4
Hybridization (cont.)
Section 9-4
Hybridization (cont.)
Section 9-4
Section 9.4
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Electronegativity and Polarity
Standard: 2f, 259
Mastering Concepts: 272(80-83)
Terms: 259
Practice Problems: 262 (49-53)
Cornell Notes: 9.4
Section Assessment: 262(54-57)
Labs: 261
Mastering 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 Polarity
Standard: 2f, 259
Mastering Concepts: 272(80-83)
Terms: 259
Practice Problems: 262 (49-53)
Cornell Notes: 9.4
Section Assessment: 262(54-57)
Labs: 261
Mastering Problems: 272(105-107)
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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
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Practice Problems: 262 (49-53)
Determine the molecular geometry, bond angle,
and type of hybridization for the following.
49. BF3
1s
1s
2s
Mix and create new
2p
Max the # unpaired
electrons available for
bonding
sp
trigonal planar, 120°, sp2
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Practice Problems: 262 (49-53)
Determine the molecular geometry, bond angle,
and type of hybridization for the following.
50. NH4+
1s
1s
2s
Mix and create new
2p
sp
tetrahedral, 109°, sp3
22
Practice Problems: 262 (49-53)
Determine the molecular geometry, bond angle,
and type of hybridization for the following.
51. OCl2
1s
1s
2s
Mix and create new
2p
sp
bent, 104.5°, sp3
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Practice Problems: 262 (49-53)
Determine the molecular geometry, bond angle,
and type of hybridization for the following.
52. BeF2
1s
1s
2s
Mix and create new
2p
sp
linear, 180°, sp
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Practice Problems: 262 (49-53)
Determine the molecular geometry, bond angle,
and type of hybridization for the following.
53. CF4
1s
1s
2s
Mix and create new
2p
sp
tetrahedral, 109°, sp3
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