1. Modern Chemistry Chapter 6 Chemical Bonding
Sections 1-5
Introduction to Chemical Bonding
Covalent Bonding & Molecular Compounds
Ionic Bonding & Ionic Compounds
Metallic Bonding
Molecular Geometry
Chapter 6 Section 2 Covalent Bonding... pages

2. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Molecule
Molecular compound
Chemical formula
Molecular formula
Bond energy
Electron-dot notation
Lewis Structure
Structural formula
Single bond
Multiple bond
Resonance
Chapter Vocabulary
Chapter 6 Section 2 Covalent Bonding... pages

3. Covalent Bonding and Molecular Compounds
Section 2
Covalent Bonding and Molecular Compounds
Chapter 6 Section 2 Covalent Bonding... pages

4. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Molecules
A neutral group of atoms that are held together by covalent bonds
Has all the physical and chemical properties of the compound
May consist of two or more atoms of the same element
Diatomic elements I2 Br2 Cl2 F2 O2 N2 H2 Molecular elements S8 P4
I Bring Clay For Our New House & Swimming Pool.
Chapter 6 Section 2 Covalent Bonding... pages

5. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Formulas
Chemical Formula – indicates the relative numbers of atoms of each kind in a chemical compound by using symbols and numeric subscripts
Molecular Formula – shows the types and number of atoms in a single molecule
Chapter 6 Section 2 Covalent Bonding... pages

6. Chemical Formula Animation
Chapter 6 Section 2 Covalent Bonding... pages

7. Formation of Covalent Bonds
p. 179
Chapter 6 Section 2 Covalent Bonding... pages

8. Formation of a Covalent Bond
Forces to consider
Electrons repel each other
Protons and electrons attract each other
e- to p+ attraction is greater than the e- to e- repulsion
Chapter 6 Section 2 Covalent Bonding... pages

9. Formation of a Covalent Bond
Potential Energy and Stability
High P.E. is related to low stability
Low P.E. is related to high stability
Chapter 6 Section 2 Covalent Bonding... pages

10. Bond Length & Stability
p. 179
Chapter 6 Section 2 Covalent Bonding... pages

11. Characteristics of Covalent Bonds
Bond Length – the distance between two bonded atoms at their minimum potential energy
Energy is released when a bond forms
The same amount of energy is required to break that bond
Bond Energy – the energy required to break a chemical bond and form neutral atoms.
Chapter 6 Section 2 Covalent Bonding... pages

12. Bond Energy & Length Table
p. 182
Chapter 6 Section 2 Covalent Bonding... pages

13. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Bond Length Animation
Chapter 6 Section 2 Covalent Bonding... pages

14. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Bond Energy Animation
p. xx
Chapter 6 Section 2 Covalent Bonding... pages

15. Noble Gas Configuration
p. 183
Chapter 6 Section 2 Covalent Bonding... pages

16. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Octet Rule
Chemical compounds tend to form so that each atom by gaining, losing or sharing electrons has an octet of electrons in its highest energy level
Chapter 6 Section 2 Covalent Bonding... pages

17. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Octet Rule Exceptions
Less than 8 electrons
Boron
Three valence electrons
Stable with only six instead of eight
Beryllium
Two valence electrons
Stable with only four instead of eight B
Always!! Be
Chapter 6 Section 2 Covalent Bonding... pages

18. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Octet Rule Exceptions
Expanded valence - involves the d orbitals as well as s & p
Phosphorus
Five valence electrons
Stable with only ten instead of eight
Sulfur
Six valence electrons
Stable with only twelve instead of eight P
Not Always!! S
Chapter 6 Section 2 Covalent Bonding... pages

19. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Octet Rule Animation
Chapter 6 Section 2 Covalent Bonding... pages

20. Lewis Structures Animation
Chapter 6 Section 2 Covalent Bonding... pages

21. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Lewis Structures
Formulas in which the symbols represent nuclei and inner shell electrons, dashes or dot-pairs between symbols represent covalent bonds and dots by one symbol represent unshared pairs.
Shared pairs = a bond
Unshared pairs = a lone pear
Chapter 6 Section 2 Covalent Bonding... pages

22. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Lone Pair Animation
Chapter 6 Section 2 Covalent Bonding... pages

23. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Structural Formula
Indicates the type, number and arrangement of the atoms and the bonds but not the unshared pairs
Chapter 6 Section 2 Covalent Bonding... pages

24. Structural Formula Animation
Chapter 6 Section 2 Covalent Bonding... pages

25. How to Draw Lewis Structures
1. Do the math to determine the number of bonds
(1 x 8) +
(3 x 2) +
(1 x 8)
= 22 e-
C H3 I _
(1 x 4) +
(3 x 1) +
(1 x 7)
= 14 e-
8 e-
/2 = 4
Divide the total by 2 to get the number of bonds in the molecule.
Subtract the “have” from the “need”.
All atoms need 8 electrons to be stable,
except H which only needs 2.
All atoms have their valence electrons available for bonding.
Chapter 6 Section 2 Covalent Bonding... pages

26. How to Draw Lewis Structures
2. Arrange the atoms as symetrically as possible, with a central atom. H H C I H
C is the central atom if it is present.
H and halogens go on the outside.
Chapter 6 Section 2 Covalent Bonding... pages

27. How to Draw Lewis Structures
3. Connect with bonds. H H C I H
If you have too many bonds, double or triple up.
Chapter 6 Section 2 Covalent Bonding... pages

28. How to Draw Lewis Structures
4. Add unshared pairs so that all atoms have 8e- (except H) H H C I H
Try page 186 #1-4 Practice.
A bond counts as two electrons.
Chapter 6 Section 2 Covalent Bonding... pages

29. Multiple Covalent Bonds
Single bond: 2 e- are shared by 2 atoms
Double bond: 4 e- are shared by 4 atoms
Triple bond: 6 e- are shared by 3 atoms
Occur commonly with C, N and O
STRONG single bond SHORT
STRONGER double bond SHORTER
STRONGEST triple bond SHORTEST
Table on page 187
Try page 188 #1 & 2 Practice
Chapter 6 Section 2 Covalent Bonding... pages

30. Multiple Bonds Animation
p. xx
Chapter 6 Section 2 Covalent Bonding... pages

31. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Resonance Structures
Bonding in molecules that cannot be correctly represented by a single Lewis structure.
Chapter 6 Section 2 Covalent Bonding... pages

32. Chapter 6 Section 2 Covalent Bonding... pages 178-189
Resonance Animation
p. xx
Chapter 6 Section 2 Covalent Bonding... pages

33. Lewis Structures Practice
C2Cl4
SCl2
AsF5
CI2Cl2
BF3
NO 1-
CH2O
IO3 1-
Lewis Structures Practice
Chapter 6 Section 2 Covalent Bonding... pages

34. Section 2 Homework Chapter 6 Section 2 Worksheet
Chapter 6 Section 2 Covalent Bonding... pages