Chemistry
Richter – revised 2011
Chapter 8
Covalent Bonding
Tues
8.1 and 8.2
Wed
HW: Read 8.1 and 8.2
: #1-20 Lewis dot only
More 8.2 VSEPR Theory
Dot and Shape
Lewis dot extension (packet pp 11-12)
HW: 21-39, 47
Thur
Fri
Mon
Tues
Resonance,
and , hybrids
HW: read 8.3
# 40-51
Bond polarity
Polar bear comic strip
HW: Read 8.4
:determine polarity of Lewis dots # 8-20
IMF’‛s
HW: polarity for all
IMF’‛s for all
Network solids
Review sheet
HW: # 52-55
Review sheet
Wed
Thur
IMF lab
Finish lab (if needed)
Go over review
Fri
Test
Objectives
8.1
Molecular Compounds – made of only non-metals
1. Describe, in terms of electron behavior, covalent bonds. (p213)
2. Define molecule, molecular compounds, and molecular formulas.
(p 214 - 215)
3. Compare the properties of molecular compounds to ionic compounds. (p214)
4. Determine the number of atoms of each element indicated by a chemical formula. (p215 -216)
8.2
The Nature of Covalent Bonding
5. Understand how the octet rule applies to covalent bonding. (p217)
6. Draw Lewis Dot structures (structural formulas) for covalent molecules and polyatomic ions
including ones that exhibit resonance and are exceptions to the octet rule. (p 218 – 229)
7. Rank single, double, and triple bonds by bond length or bond strength.
8. Define a coordinate covalent bond. (p223)
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Chemistry
Richter – revised 2011
9. What is bond dissociation energy and what does it indicate a bout the strength of a bond?
(p 226)
8.3
Bonding Theories
10. Define molecular orbitals. (p230)
11. Compare sigma and pi bonds. (p230-231)
12. Use the VESPR theory to determine the geometry of a molecule. (p232-233)
13. Determine the hybridization of the central atom of a molecule. (p234-236)
8.4
Polar Bonds and Molecules
14. Describe, in terms of electron behavior, polar bonds vs. non-polar bonds. (p237 -238)
15. Classify bonds as non-polar covalent, polar covalent, or ionic based on the electronegativity
difference of the elements forming the bond. (p238)
16. Identify molecules as being polar or non polar and use + and - symbols and an arrow to
17.
18.
19.
20.
indicate the dipoles of a polar molecule. (p239 – 240)
Rank dispersion forces, dipole-dipole forces, and hydrogen bonding by relative strength.
(p240-241)
Identify the type of IMF a material has by drawing the Lewis dot structure for it.
Relate the size of atoms or molecules to the magnitude of the dispersion forces they feel.
Define network solids and identify the types of bonding they have.
Pulling Chapters 7 & 8 Together
21. Compare the types of binding forces of different materials in terms of melting and boiling
point, and conductivity when dissolved or melted.
1. Ionic
2. Network Solid
3. Metallic
4. Molecular
Hydrogen bonding
Dipole-dipole
Dispersion
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Chemistry
Richter – revised 2011
8.1 Molecular compounds
1.
Chapter 8 Practice
How are the melting and boiling points of molecular compounds different from those of ionic
compounds? Much lower
2. List the 7 diatomic elements. H2 , N2 , O2 , F2 , Cl 2 , Br2 , I2
3. How many atoms of each type are represented by the molecular formula for ethanol: C 2 H6 O?
C–2
H-6
O-6
4. A covalent bond forms when two atoms _share__ a pair of electrons.
8.2 The Nature of Covalent Bonding
5. A dash in a Lewis dot structure represents _2 bonded_ electrons.
6. How many unshared pairs of electrons are in a water molecule? Draw it.
2
7. How many electrons are shared in a double bond? _4__ A triple bond? _6__
Molecule Lewis Dot
8.
PCl3
9
CS2
10.
SBr2
11.
SiF2Br2
12.
COI2
Shape
pyramidal
Polarity Hybrid
P
sp3
IMF
D
D-D
NP
sp
D
P
sp3
D
D-D
sp3
D
sp2
D
D-D
107˚
Linear
180˚
Bent
105˚
Tetrahedral
109˚
Trigonal
planar
P
120˚
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Chemistry
Richter – revised 2011
13.
Trigonal
planar
BCl3
120˚
14.
Tetrahedral
CCl4
15.
Trigonal
Planar
120˚
16.
Linear
17.
PF3
18.
PO4319.
D
NP
sp3
D
P
sp2
D
D-D
NP
sp2
D
P
sp3
D
D-D
NP
sp3
D
NP
sp2
D
P
sp3
D
D-D
180˚
Pyramidal
107˚
Tetrahedral
109˚
Trigonal
planar
AlCl3
120˚
20.
Bent
SI2
sp2
109˚
SiOH2
O2
NP
180˚
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Chemistry
Richter – revised 2011
21.
IO322.
H2Se
23.
P
sp3
D
D-D
P
sp3
D
D-D
Linear
NP
sp
D
Trigonal
planar
NP
sp2
D
NP
sp3
D
P
sp3
D
D-D
Linear
P
sp3
D
D-D
Pyramidal
P
sp3
D
D-D
H-bond
Pyramidal
107˚
Bent
105˚
N2
24.
BH3
25.
CBr4
26.
BiH3
27.
120˚
Tetrahedral
109˚
Pyramidal
107˚
HCl
28
H3O+
107˚
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Chemistry
Richter – revised 2011
29.
SO4230.
SiO2
31.
NCl3
32.
Tetrahedral
NP
sp3
D
NP
sp
D
NP
sp3
D
NP
sp2
D
109˚
Linear
180˚
Pyramidal
107˚
Trigonal
planar
BF3
120˚
33.
Linear
P
sp3
D
D-D
Tetrahedral
P
sp3
D
D-D
NP
sp2
D
P
sp3
D
D-D
H-bond
HI
34.
CH3Cl
35.
109˚
Trigonal
planar
CF2O
120˚
36.
Pyramidal
NH3
107˚
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Chemistry
Richter – revised 2011
37.
CO2
38.
Linear
Trigonal
planar
120˚
39.
Bent
40.
XeF2
41.
BrF3
42.
sp
D
NP
sp2
D
P
sp3
D
D-D
NP
sp3d
D
P
sp3d
D
D-D
NP
sp3d2
D
180˚
AlH3
OCl2
NP
105˚
Linear
180˚
t-shaped
90˚
Square
planar
XeF4
90˚
43.
Seesaw
P
sp3d
D
D-D
Seesaw
P
sp3d
D
D-D
SF4
44.
SeH4
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Chemistry
Richter – revised 2011
45.
XeCl2
46.
PCl647.
PCl5
48.
ClF5
49.
SeCl6
50.
NP
sp3d
D
NP
sp3d2
D
NP
sp3d
D
Squarw
based
pyramid
P
sp3d2
D
D-D
Octahedral
NP
sp3d2
D
Pentagonal
bipyramid
NP
sp3d3
D
t-shaped
P
sp3d
D
D-D
Linear
180˚
Octahedral
90˚
Trigonal
bipyramidal
90˚, 120 ˚
90˚
IF7
51.
ICl3
90˚
52.
A covalent bond where the two electrons that form the bond are both contributed by one atom
is called a ___________________________bond.
53.
If PH3 bonded with BH3 , the P would bond with the B. Which atom would contribute the two
electrons?
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Chemistry
Richter – revised 2011
54.
If a substance has a small dissociation energy, it means it has a relatively (strong/weak) covalent
bond.
55. Draw the Lewis dot structures of the following molecules which exhibit resonance.
a. NO3-
b. SO2
c. CO3-2
d. NO2-
56. What elements are common exceptions to the octet rule? (p 228-229) Be, B, any after P
Section 8.3 Bonding Theories
57. What is the difference in terms of electron location between a and a bond?
σ directly between atoms
π side by side overlap of vertical p orbitals
58. Complete the chart below:
Lewis Dot Structure
H 2 CO
# of
bonds
3
# of
bonds
1
CN-
1
2
H2
1
0
Section 8.4 Polar Bonds and Molecules
59.
Determine the polarity for all of the molecules in #8-#39. Draw arrows and +/drawing.
signs on each
60.
Dispersion is the attraction between particles that have temporary charges caused by
____normal movement of electrons______. It is the (weakest/strongest) IMF.
61.
Dipole-dipole attractions are between two molecules that are both _polar_______.
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Chemistry
Richter – revised 2011
62.
Hydrogen bonding occurs between two molecules that have the element _H_ attached to either
_F__, _O_____, or __N___. This IMF is the
(strongest/weakest).
63.
Determine the IMF that all the molecules exhibit for #8-39.
64.
What are the properties of network solids?
65.
Why would it be harder to melt a network solid than a molecular solid?
66.
In what ways are network solids like molecular solids? Answer in terms of the types of bonds
inside them and in terms of their properties.
67.
How are network solids similar to ionic solids? Answer in terms of particle arrangement and in
terms of properties.
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Chemistry
Richter – revised 2011
Lewis Dot Extention - Exceeding the Octet Rule
Name: _____________________
Draw the Lewis Dot structure for each molecule and name it’‛s shape.
1. XeF2
2. BrF3
3. XeF4
4. SF4
5. SeH4
6. XeCl 2
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Chemistry
Richter – revised 2011
7. PCl 6-
8. PCl 5
9. ClF5
10. SeCl 6
11. IF7
12. ICl 3
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Chemistry
Richter – revised 2011
Chapter 8 Review
1.
8.1
Contrast ionic bonds and covalent bonds. __ionic – metal and nonmetal, transfer of electrons
___covalent – all nonmetals, sharing of electrons __________________________________
2. List the 7 diatomic elements. __H2 , N2 , O2 , F2 , Cl 2 , Br2 , I2 _____________________________
3. Contrast the properties of molecular compounds with ionic compounds. __molecular – low melting
point ________________________________________________________ ___________
___ionic- high melting point, brittle, conduct in solution and as a liquid.___________________
4. Which of the following compounds is molecular?
a) NaBr
b) H2 S
c) AlCl 3
d) CaO
5. Identify how many atoms of the underlined element are in the compounds listed.
__3_a) CaCO3
__4__b) H2 SO4
__1_c) H2 CO3
__9__d) Al(NO3 )3
__12_e) (NH4 )3 P
8.2
6. How many electrons are shared in each type of bond?
_____ single bond
______ double bond ______ triple bond
7. Which type of bond in the problem above is a) strongest
a) ________________________
b) weakest
b) _____________________
8. What is a lone pair (unshared pair)? ____________________________________________
9. Which of the following is not a polyatomic ion?
a) CO3 2-
b) SO4 2-
c) Co2+
d) NH4 +
10. How are coordinate covalent bonds different from other covalent bonds?
________________________________________________________________________
11. Which would have a higher bond dissociation energy?
a) O2
b) N2
12. Which would be harder to break apart?
a) Substance A with bond dissociation value of 700 kJ/mol
b) Substance B w ith bond dissociation value of 800 kJ/mol
13. Review the resonance structures worksheet.
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Chemistry
Richter – revised 2011
8.3
14. Go back through your Chapter 8 worksheet and put a * by any substance that has an exception
to the octet rule in its central atom.
15. What is a molecular orbital? _________________________________________________
16. Give the number of σ and π bonds in each molecule.
a)
HCl
_____σ and _____π
b) O2
_____σ and _____π
c) N2
_____σ and _____π
17. Explain in your own words what the VSEPR Theory is.
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
18. Review the Lewis Dot structures and hybrid columns on the Chapter 8 worksheet.
8.4
19. Determine if the following bonds would be polar covalent or non -polar covalent or ionic.
a) H and Br
b) Cs and Cl
c) N and P
d) O & O
20. Review the Chapter 8 worksheet where you determined if the molecule is polar or not.
21. Review the Chapter 8 worksheet where you determined the type of IMF each molecular
substance has.
22. Which would have the greatest dispersion?
a) C2 H6
b) C3 H8
c) C4 H1 0
23. How is a network solid different from a molecular solid?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
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Chemistry
Richter – revised 2011
24. For the following descriptions use the following choices: a) dispersion
b) dipole -dipole c)
hydrogen bonding
_____ a. The force between SO2 molecules
_____ b. The force that makes HF a liquid at room temperatures
_____ c. The force which results from temporary, induced dipoles
_____ d. The type of force felt by H 2 and F2
_____ e. The type of IMF felt by the noble gases
Tying Chapter 7 & 8 together:
25. Complete the following table:
Ionic
Metallic
Molecular
Network Solid
Melting point
(high/low)
Boiling point
(high/low)
Physical state @
room temp
(solid/liquid/gas)
Thermal
/Electrical
Conductivity
(high/low)
26. At room temperature, substance A is a solid, substance B is a liquid and substance C is a gas.
a) Which material has the greatest IMF?
b) Which material is most orderly?
c) Which is the best conductor of heat (thermal energy)?
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