Title: Chemical%20Bonding
1 2- Chemical Bond
- attractive force between atoms or ions that binds
them together as a unit - bonds form in order to
- decrease potential energy (PE)
- increase stability
3COMPOUND
more than 2 elements
2 elements
Ternary Compound
Binary Compound
NaNO3
NaCl
4ION
1 atom
2 or more atoms
Polyatomic Ion
Monatomic Ion
NO3-
Na
5Types of Bonds
COVALENT
IONIC
e- are transferred from metal to nonmetal
e- are shared between two nonmetals
Bond Formation
Type of Structure
true molecules
crystal lattice
Physical State
liquid or gas
solid
Melting Point
low
high
Solubility in Water
yes
usually not
yes (solution or liquid)
Electrical Conductivity
no
Other Properties
odorous
6 Types of Bonds
METALLIC
e- are delocalized among metal atoms
Bond Formation
Type of Structure
electron sea
Physical State
solid
Melting Point
very high
Solubility in Water
no
yes (any form)
Electrical Conductivity
malleable, ductile, lustrous
Other Properties
7Ionic Bonds
8Ionic Bonding - Crystal Lattice
9Covalent Bonding - True Molecules
Diatomic Molecule
10Metallic Bonding - Electron Sea
11Bond Polarity
- Most bonds are a blend of ionic and covalent
characteristics. - Difference in electronegativity determines bond
type.
12Bond Polarity
- Electronegativity
- Attraction an atom has for a shared pair of
electrons. - higher e-neg atom ? ?-
- lower e-neg atom? ?
13Bond Polarity
- Electronegativity Trend (p. 151)
- Increases up and to the right.
14Bond Polarity
- Nonpolar Covalent Bond
- e- are shared equally
- symmetrical e- density
- usually identical atoms
15- Polar Covalent Bond
- e- are shared unequally
- asymmetrical e- density
- results in partial charges (dipole)
16 17Bond Polarity
3.0-3.00.0 Nonpolar 3.0-2.10.9 Polar 3.0-0.92.1
Ionic
18- Chemical Bond
- attractive force between atoms or ions that binds
them together as a unit - bonds form in order to
- decrease potential energy (PE)
- increase stability
19Lewis Diagrams
20Rule
- Remember
- Most atoms form bonds in order to have 8 valence
electrons.
21A. Octet Rule
- Groups 1,2,3 get 2,4,6 valence e-
- Expanded octet ? more than 8 valence e- (e.g. S,
P, Xe)
- Radicals ? odd of valence e-
22B. Drawing Lewis Diagrams
- Find total of valence e-.
- Arrange atoms - singular atom is usually in the
middle. - Form bonds between atoms (2 e-).
- Distribute remaining e- to give each atom an
octet (recall exceptions). - If there arent enough e- to go around, form
double or triple bonds.
23B. Drawing Lewis Diagrams
1 C 4e- 4e- 4 F 7e- 28e- 32e-
F F C F F
- 8e- 24e-
24B. Drawing Lewis Diagrams
1 Be 2e- 2e- 2 Cl 7e- 14e- 16e-
- 4e- 12e-
25B. Drawing Lewis Diagrams
1 C 4e- 4e- 2 O 6e- 12e- 16e-
- 4e- 12e-
26C. Polyatomic Ions
- To find total of valence e-
- Add 1e- for each negative charge.
- Subtract 1e- for each positive charge.
- Place brackets around the ion and label the
charge.
27C. Polyatomic Ions
1 Cl 7e- 7e- 4 O 6e- 24e- 31e-
O O Cl O O
1e- 32e-
- 8e- 24e-
28C. Polyatomic Ions
1 N 5e- 5e- 4 H 1e- 4e- 9e-
H H N H H
- 1e- 8e-
- 8e- 0e-
29D. Resonance Structures
- Molecules that cant be correctly represented by
a single Lewis diagram. - Actual structure is an average of all the
possibilities. - Show possible structures separated by a
double-headed arrow.
30D. Resonance Structures
31Molecular Geometry
32VSEPR Theory
- Valence Shell Electron Pair Repulsion Theory
- Electron pairs orient themselves in order to
minimize repulsive forces.
33VSEPR Theory
- Types of e- Pairs
- Bonding pairs - form bonds
- Lone pairs - nonbonding e-
34VSEPR Theory
- Lone pairs reduce the bond angle between atoms.
35Determining Molecular Shape
- Draw the Lewis Diagram.
- Tally up e- pairs on central atom.
- double/triple bonds ONE pair
- Shape is determined by the of bonding pairs and
lone pairs.
36Common Molecular Shapes
LINEAR 180
37Common Molecular Shapes
TRIGONAL PLANAR 120
38Common Molecular Shapes
BENT lt120
39Common Molecular Shapes
TETRAHEDRAL 109.5
40Common Molecular Shapes
TRIGONAL PYRAMIDAL 107
41Common Molecular Shapes
BENT 104.5
42Common Molecular Shapes
TRIGONAL BIPYRAMIDAL 120/90
43Common Molecular Shapes
OCTAHEDRAL 90
44Examples
4 total 3 bond 1 lone
TRIGONAL PYRAMIDAL 107
45Examples
2 total 2 bond 0 lone
LINEAR 180
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