Covalent Bonding
Chap. 9
I. Why does it form?
I. Why does it form?
A. Octet rule
An atom will gain, lose, or share
electrons in order to get a full set
I. Why does it form?
A. Octet rule
B. Stability/Minimum energy
I. Why does it form?
II. What is a molecule?
Molecule = covalent compound
I. Why does it form?
II. What is a molecule?
A. Non-metal with a non-metal
I. Why does it form?
II. What is a molecule?
A. Non-metal with a non-metal
B. Some molecules are diatomic
Molecules made of two of the
same atom
I. Why does it form?
II. What is a molecule?
A. Non-metal with a non-metal
B. Some molecules are diatomic
C. Properties
Properties of Covalent Compounds
1. Often are gases or liquids
Properties of Covalent Compounds
1. Often are gases or liquids
2. Tend to have lower M.P.
Properties of Covalent Compounds
1. Often are gases or liquids
2. Tend to have lower M.P.
3. Often are soft
Properties of Covalent Compounds
1. Often are gases or liquids
2. Tend to have lower M.P.
3. Often are soft
4. Many are non-electrolytes
III. Representing Molecules
Lewis structure uses dots and dashes
to represent electrons and bonds
III. Representing Molecules
IV. Covalent Bond types
III. Representing Molecules
IV. Covalent Bond types
A. Single bond
Bond made of one pair of
shared electrons
III. Representing Molecules
IV. Covalent Bond types
A. Single bond
B. Double bond
Bond made of two pairs of
shared electrons
III. Representing Molecules
IV. Covalent Bond types
A. Single bond
B. Double bond
C. Triple bond
Bond made of three pairs of
shared electrons
III. Representing Molecules
IV. Covalent Bond types
A.
B.
C.
D.
Single bond
Double bond
Triple bond
Quadruple bond?
III. Representing Molecules
IV. Covalent Bond types
V. Bond strength
Bond energy measures the bond
strength.
III. Representing Molecules
IV. Covalent Bond types
V. Bond strength
A. The longer the bond the
______ the bond energy
III. Representing Molecules
IV. Covalent Bond types
V. Bond strength
A. The longer the bond the
______ the bond energy
B. Double bonds require
_____ energy to break
than single bonds.
Bond energy example
What is the energy change for
this reaction? Is it exothermic?
H2 + Cl2
H-H
436 kJ
Cl-Cl
242 kJ
HCl
431 kJ
2HCl
VI. Naming Covalent
Compounds
VI. Naming Covalent
Compounds
A. Binary Inorganic
Molecules
Rules for Naming
Covalent Compounds
Rules for Naming
Covalent Compounds
1. Name the first. . .
Rules for Naming
Covalent Compounds
1. Name the first. . .
2. Name the second with. . .
Rules for Naming
Covalent Compounds
1. Name the first. . .
2. Name the second with. . .
3. Use prefixes to tell. . .
Rules for Naming
Covalent Compounds
1. Name the first. . .
2. Name the second with. . .
3. Use prefixes to tell. . .
4. Never begin name with . . .
Prefixes for
Numbers of Atoms
Prefixes for
Numbers of Atoms
1. mono-
Prefixes for
Numbers of Atoms
1. mono2. di-
Prefixes for
Numbers of Atoms
1. mono2. di3. tri-
Prefixes for
Numbers of Atoms
1. mono2. di3. tri4. tetra-
Prefixes for
Numbers of Atoms
1. mono2. di3. tri4. tetra-
5. penta-
Prefixes for
Numbers of Atoms
1. mono2. di3. tri4. tetra-
5. penta-
6. hexa-
Prefixes for
Numbers of Atoms
1. mono2. di3. tri4. tetra-
5. penta-
6. hexa7. hepta-
Prefixes for
Numbers of Atoms
1. mono2. di-
6. hexa7. hepta-
3. tri-
8. octa-
4. tetra-
5. penta-
Prefixes for
Numbers of Atoms
1. mono2. di-
6. hexa7. hepta-
3. tri-
8. octa-
4. tetra-
9. nona-
5. penta-
Prefixes for
Numbers of Atoms
1. mono2. di-
6. hexa7. hepta-
3. tri-
8. octa-
4. tetra-
9. nona-
5. penta-
10. deca-
Rules for Naming
Covalent Compounds
1. Name the first. . .
2. Name the second with. . .
3. Use prefixes to tell. . .
4. Never begin name with. . .
VI. Naming Covalent
Compounds
A. Binary Inorganic
Molecules
B. Common Names
VI. Naming Covalent
Compounds
A. Binary Inorganic
Molecules
B. Common Names
C. Organic Molecules
Covalent compounds with carbon
Names for organic
hydrocarbons
Names for organic
hydrocarbons
CH4
methane
Names for organic
hydrocarbons
CH4
methane
C2H6
ethane
Names for organic
hydrocarbons
CH4
methane
C2H6
ethane
C3H8
propane
Names for organic
hydrocarbons
CH4
methane
C2H6
ethane
C3H8
propane
C4H10
butane
Names for organic
hydrocarbons
CH4
methane
C2H6
ethane
C3H8
propane
C4H10
butane
C5H12
pentane
Names for organic
hydrocarbons
C6H14
C7H16
C8H18
C9H20
C10H22
Names for organic
hydrocarbons
C6H14
hexane
C7H16
C8H18
C9H20
C10H22
Names for organic
hydrocarbons
C6H14
hexane
C7H16
heptane
C8H18
C9H20
C10H22
Names for organic
hydrocarbons
C6H14
hexane
C7H16
heptane
C8H18
octane
C9H20
C10H22
Names for organic
hydrocarbons
C6H14
hexane
C7H16
heptane
C8H18
octane
C9H20
nonane
C10H22
Names for organic
hydrocarbons
C6H14
hexane
C7H16
heptane
C8H18
octane
C9H20
nonane
C10H22
decane
Self Check 1
Write the names for these compounds
PF3
SF6
CS2
SiH4
Self Check 2
Write the formulas for these compounds
Carbon tetrachloride
Diphosphorus decachloride
VI. Naming Covalent
Compounds
D. Naming acids
Acids are hydrogen-donating compounds
VI. Naming Covalent
Compounds
D. Naming acids
1. Binary Acids
Acids composed of H+ ion and a
monatomic anion.
Rules for Naming Acids
Anion Name
chloride
Acid Name
Formula
Hydrochloric acid
Rules for Naming Acids
Anion Name
Acid Name
Formula
chloride
Hydrochloric acid
fluoride
Hydrofluoric acid
Rules for Naming Acids
Anion Name
Acid Name
Formula
chloride
Hydrochloric acid
fluoride
Hydrofluoric acid
bromide
??
Rules for Naming Acids
Anion Name
Acid Name
Formula
chloride
Hydrochloric acid
fluoride
Hydrofluoric acid
bromide
Hydrobromic acid
Rules for Naming Acids
Anion Name
Acid Name
Formula
chloride
Hydrochloric acid
fluoride
Hydrofluoric acid
bromide
Hydrobromic acid
____-ide
Hydro____ic acid
VI. Naming Covalent
Compounds
D. Naming acids
1. Binary Acids
2. Oxyacids
Acids composed of H+ ion and a
polyatomic anion containing oxygen.
Rules for Naming Oxyacids
Anion Name
chlorate
Acid Name
Chloric acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorate
Chloric acid
nitrate
Nitric acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorate
Chloric acid
nitrate
Nitric acid
sulfate
??
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorate
Chloric acid
nitrate
Nitric acid
Sulfate
Sulfuric acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorate
Chloric acid
nitrate
Nitric acid
Sulfate
Sulfuric acid
______ate
______ic acid
Formula
Rules for Naming Oxyacids
Anion Name
chlorite
Acid Name
Chlorous acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorite
Chlorous acid
nitrite
Nitrous acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorite
Chlorous acid
nitrite
Nitrous acid
sulfite
??
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorite
Chlorous acid
nitrite
Nitrous acid
sulfite
Sulfurous acid
Formula
Rules for Naming Oxyacids
Anion Name
Acid Name
chlorite
Chlorous acid
nitrite
Nitrous acid
sulfite
Sulfurous acid
____ite
______ous acid
Formula
Self Check 3
Write the formulas for these compounds
Carbonic acid
Phosphoric acid
Acetic acid
VII. Structural Formulas
A Lewis structure shows which atoms
are bonded to which.
VII. Structural Formulas
A. Valence electrons important
Valence electrons = outermost
electrons.
VII. Structural Formulas
A. Valence electrons important
1. Bonding Electrons
Pair of electrons shared between two
elements.
VII. Structural Formulas
A. Valence electrons important
1. Bonding Electrons
2. Lone pairs
Pair of electrons not being shared.
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
1. for molecules
Rules for Lewis Structures
1. Determine the total . . .
Rules for Lewis Structures
1. Determine the total . . .
2. Join all elements with . . .
Rules for Lewis Structures
1. Determine the total . . .
2. Join all elements with . . .
3. Arrange remaining . . .
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
1. for molecules
2. for molecules with multiple bonds
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
1. for molecules
2. for molecules with multiple bonds
3. for ions
Self Check 4
Draw a Lewis structure for:
CH3Cl
CS2
Phosphorus trifluoride
Dichlorine monoxide
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
1. for molecules
2. for molecules with multiple bonds
3. for ions
4. resonance structures
Resonance
Concept that a molecule is
described by more than one
structure
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
C. Exceptions
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
C. Exceptions
1. odd number of electrons
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
C. Exceptions
1. odd number of electrons
2. less than an octet
VII. Structural Formulas
A. Valence electrons important
B. Drawing a Lewis structure
C. Exceptions
1. odd number of electrons
2. less than an octet
3. more than an octet
VIII. Molecular Shape
VIII. Molecular Shape
A. VSEPR Theory
Valence shell electron pair repulsion
theory: electrons are placed at
maximum distances from other
electrons
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
3. Tetrahedral (CH4)
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
3. Tetrahedral (CH4)
a. trigonal pyramidal (NH3)
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
3. Tetrahedral (CH4)
a. trigonal pyramidal
b. bent
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
3. Tetrahedral (CH4)
4. Trigonal bipyramidal
VIII. Molecular Shape
A. VSEPR Theory
B. Molecular Shapes
1. Linear (BeCl2)
2. Trigonal planar (BF3)
3. Tetrahedral (CH4)
4. Trigonal bipyramidal
5. Octahedral
IX. Polarity
IX. Polarity
A. When is a bond polar?
Polar bonds occur when electrons are
shared unequally.
Bond types
Electronegativity
Difference
Bond
Type
Bond types
Electronegativity
Difference
0.0 – 0.4
Bond
Type
non-polar covalent
Bond types
Electronegativity
Difference
Bond
Type
0.0 – 0.4
non-polar covalent
0.5 – 1.9
polar covalent
Bond types
Electronegativity
Difference
Bond
Type
0.0 – 0.4
non-polar covalent
0.5 – 1.9
polar covalent
1.9 -
ionic
“COVALENT”
Bond types
0.5
1.0
1.5
2.0
Electronegativity Difference
2.5
3.0
3.5
IX. Polarity
A. When is a bond polar?
B. When is a molecule polar?
Polar molecules contain polar bonds
and are NOT symmetrical.
Self Check 5
Are the bonds in ammonia (NH3)
polar?
Is the molecule polar?
The End