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Unit 5b: Bonding and Shape
(Link to Prentice Hall Text: Chapters 15 & 16)
Date Due
Assignments
Page Number: Problem Numbers
Assignment 1: Ionic Bonding
432: 23, 25, 26, 44
470: 53
Assignment 2: Covalent Lewis Structures
470: 30, 32, 33, 37, 38, 41
Assignment 3: Molecular Geometry, Sigma + Pi
470: 47, 48, 63
Assignment 4: Hybridization
470: 50, 66
Assignment 5: Polarity
470: 52, 54
Assignment 6: Coordinate Covalent Bonds
470: 34
Assignment 7: Metallic Bonding
432: 39
Assignment 8: Intermolecular Forces
470: 55, 56, 57, 58
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A. What is a Chemical Bond?
The Nature of the Chemical Bond
A chemical bond is best described as an ____________________________________________________.
Chemical bonds are created due to forces between ______________ and ________________ within an
atom.
____________________________to break a chemical bond or ______________. It is an
_____________________________ process.
When a chemical bond forms,________________________________________. It is an
_____________________________ process.
B. Valence Dot Structures for Atoms
Valence Number Periodicity
Group
Period
2
Ion
3
Ion
1
2
13
15
16
17
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C. Properties of Ionic Compounds
Ionic Dot Structures
1. Why do metals tend to lose electrons and non-metals tend to gain electrons?
Metals: ________________________________________________________
Non-metals:____________________________________________________
2. What electron configuration does each atom attain in an ionic compound?
Each atom attains the electron configuration of a ______________________
Ionic Dot Structures
When writing Lewis Diagrams for ionic compounds, simply show the Lewis Dot Structure for each
individual ion (include charge), and put the atoms in brackets. Draw the Lewis Diagram for each of the
following ionic compounds.
1. NaCl
Name:
2. LiF
3. CaO
Name:
4. MgS
Name:
5. MgCl2
Name:
6. CaI2
Name:
7. RbBr
Name:
8. SrF2
Name:
Name:
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Lewis Diagrams for Covalent Compounds
The bonds for covalent compounds do not involve the transfer of electrons. Covalent
compounds involve the sharing of electrons.
Vocab
Lone pairSingle covalent bond-
Double covalent bond-
Triple covalent bond-
Resonance-
General Guidelines for Drawing Lewis Diagrams for Covalent Compounds
Step 1: Count the total number of valence electrons.
Step 2: Assemble the bonding framework (skeleton). Place the least electronegative element in the
center.
Step 3: Arrange the remaining electrons so that each atom has 8 electrons around it (the octet rule). If
necessary, place additional pairs of electrons between the atoms to form additional bonds.
Step 4: Check for exceptions to the octet rule.
Step 5: Evaluate whether the formal charges (FC) on the atoms are reasonable.
Step 6: If necessary, draw resonance structures.
Formal Charge =
Drawing Lewis Structures with Simple Single, Double and Triple Bonds
Use the rules above to draw Lewis structures for the following compounds.
1. CH4
Molecular Geometry:___________________
2. H2S
Molecular Geometry:___________________
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3. PH3
Molecular Geometry:___________________
5. H2O
Molecular Geometry:___________________
7. C2H4
Molecular Geometry:___________________
9. CH3Br
Molecular Geometry:___________________
11. C2H3Cl
Molecular Geometry:___________________
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4. NH3
Molecular Geometry:___________________
6. SF4
Molecular Geometry:___________________
8. OH-
Molecular Geometry:___________________
10. CO32-
Molecular Geometry:___________________
12. CO2
Molecular Geometry:___________________
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13. SO3
Molecular Geometry:___________________
15. XeF4
Molecular Geometry:___________________
17. SCN-
Molecular Geometry:___________________
19. NI3
Molecular Geometry:___________________
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14. N2O
Molecular Geometry:___________________
16. NO3-
Molecular Geometry:___________________
18. C3H8
Molecular Geometry:___________________
20. BF3
Molecular Geometry:___________________
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D. Summary of Hybridization and Molecular Geometry
Central
Electron Pairs
2
Electron
Geometry
Linear
Number of
Bond Clouds
2
3
Trigonal planar
2
3
Trigonal planar
3
4
Tetrahedral
2
4
Tetrahedral
3
4
Tetrahedral
4
5
Trigonal
bipyramidal
2
5
Trigonal
bipyramidal
3
5
Trigonal
bipyramidal
4
5
Trigonal
bipyramidal
5
6
octahedral
2
6
octahedral
3
6
octahedral
4
6
octahedral
5
6
octahedral
6
Bond Angles
Molecular Geometry / Shape
Hybridization
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E. Three-Dimensional Representations of Covalent Compounds
The following are VSEPR (Valence Shell Electron Pair Repulsion) geometries for covalent compounds.
VSEPR is based on the idea that regions of electrons (either lone pairs or bonds) will repel to seek the
configuration where they are the furthest apart, and therefore the most stable.
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F. Hybridization of Orbitals
Valence Bond Theory (Linus Pauling) – In order for atoms to bond, orbitals must overlap.
sp
Example: BeCl2
sp2
Example: BF3
sp3
Example: CH4
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G. Sigma and Pi Bonds
Determining Number of Sigma and Pi Bonds
Single Bonds Consist of: __________________________________________________
Double Bonds Consist of:________________________________________________
Triple Bonds Consist of:___________________________________________________
H. Bond Polarity and Molecular Polarity
Determining the Polarity of a Bond
If two atoms, with a bond between them, have different electronegativities, the bond is
described as __________________________________________.
Polar covalent bonds have an end that is partially _____________________and partially
_________________________ in charge. A polar bond is said to have a
______________________ .
Nonpolar covalent bonds have no charge separation.
Scale:
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Determining the Polarity of a Compound
If a molecule is symmetrical, the molecule is __________________________________________.
If a molecule is nonsymmetrical, the molecule is _______________________________________.
Determining Molecular Polarity
Draw the Lewis Structures for the following compounds and determine whether they are polar or
nonpolar. Important: Place lone pairs on the same atom adjacent to each other.
1. HCl
2. CO2
3. CCl4
4. H2O
5. O2
6. C2HCl
7. HCN
8. C2H4
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Compounds Containing Ionic and Covalent Bonds
Identifying Compounds with Ionic and Covalent Bonds
Ionic compounds that contain _____________________________________ ions contain both ionic and
covalent bonding.
1. Sodium nitrate
2. K3PO4
3. KNO2
4. Ammonium chloride
I. Coordinate Covalent Bonds
Identifying Coordinate Covalent Bonds
In some cases one atom donates all of the electrons to a bond. In this case, it is called a
coordinate covalent bond.
Example 1: NH4+
Example 2: H3O+
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J. Intermolecular Forces: Influence on Vapor Pressure and Boiling Points
Three Types of Intermolecular Forces
Intramolecular forces:
Intermolecular Forces:
As forces of attraction between molecules increase, the:
(1) Vapor Pressure __________________________________________________
(2) Boiling Point
__________________________________________________
A. Intermolecular Force (1): Hydrogen Bonding Force - STRONGEST
Occurs only between molecules that have a _________ atom bonded to a fluorine, oxygen
or nitrogen atom.
B. Intermolecular Force (2): Dipole-Dipole Force - INTERMEDIATE
Occurs between __________________ molecules.
C. Intermolecular Force (3): Dispersion (van der Waals) Force - WEAKEST
Occurs between ____________________ molecules. As the mass of the molecule/atom
increases, the van der Waals forces.
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K. Distinguishing Ionic, Metallic, Molecular and Covalent Network Solids
Differences in Bond Type in Various Solids
Example
Picture
Properties
Ionic Solid
Metallic Solid
Molecular Solid
Covalent
Network Solid
Metals are atoms that have
low ionization energies and a
small number of valence
electrons. The inner
electrons of metal atoms are
arranged in a crystalline
lattice. The valence electrons
move freely throughout the
lattice and are not attached
to any one atom in particular.