Chapter 6: Chemical Bonding
Objectives
 Describe covalent, ionic bonds and metallic bonds.
 Classify bond type by electronegative difference
 Explain why atoms form bonds
 Draw Lewis structures
 Classify covalent and ionic compounds by physical properties
 Predict molecular geometry using VSEPR theory
A. Vocabulary
Chemical bond
A. attractive force between atoms or ions that _________________________
B. Bonds form in order to…
1)
2)
CHEMICAL FORMULA
ION
B. Basics of Ionic and
Covalent Bonds
Bond Type:
Electrons are…
Ionic
Covalent
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Types of Structure:
C. Bond Polarity
Electronegativity
1)
2) In covalent molecules:
a)
3)
4)
Nonpolar Covalent Bond
1.
2.
3.
Polar Covalent Bond
1.
2.
3.
-2-
% Ionic Character
Difference in electronegativity
b)
Examples
Elements
Electronegative
difference
Bond Type
More negative
atom
H&S
Cs & S
S & Cl
C&H
O&O
D. Bond Formation
E. Lewis Structures
- Electron dot notation
-
Electron dot
examples
Na
Mg
Al
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C
N
O
F
Ne
Octet Rule
- Octet Rule
- Structural formulas and Lewis Structures
What is the difference?
For covalent bonds:
Element
Hydrogen
Group 1*
Valence e-
Bonds
Group 2*
Group (boron)
Carbon
Nitrogen
Oxygen
Halogens
* Note that Group 1 and 2 metals usually form Ionic bonds.
-4-
Octet Rule
E. Lewis Structures
Examples
Covalent –
Ionic –
NaCl =
CH4 =
CaCl2 =
C2H4 =
F2 =
N2 =
H2O =
CH2O2 =
F. Bond Traits:
IONIC
COVALENT
METALLIC
Bond Formation
Type of Structure
Physical State
Melting Point
Solubility in Water
Electrical
Conductivity
Other properties
G. VSEPR Theory
________________________ orient themselves in order to minimize repulsive forces.
Types of Electron Pairs
 _____________________________ - Form bonds
 _____________________________ - nonbonding electrons.
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Bonding chart with
Examples:
H. Common VSEPR
Shapes
Formula
Bonded e-
Lone
pairs
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2D
drawing
Shape name
I. Metallic Bonding
Malleability –
Ductility –
Explain electron sea
J. Intermolecular Forces
____________________________ - polar covalent molecules where there is an asymmetrical
electron density across the entire molecule (not just in the bonds)
________________________________________ - occur when dipoles line up and attract each
other
K. Hydrogen Bonds
L. London dispersion
Forces
_____________________________ - super dipole-dipole interactions between δ+ on hydrogen
and δ- charges on other parts of a molecule
________________________________ - are the attractive forces between temporary dipoles
created by random motion of electrons
The more e- involved, the _____________________ the London dispersion forces
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