1. Chapter 8 Covalent Bonding 8.1 Molecular Compounds
8.2 The Nature of Covalent Bonding
8.3 Bonding Theories
8.4 Polar Bonds and Molecules
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

2. Molecules and Molecular Compounds
Do Now (Part I): Classify as ionic or covalent
Sodium Chloride, NaCl
Methane, CH4
Oxygen, O2
Ammonia, NH3
Magnesium Oxide, MgO
Barium Iodide, BaI2
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

3. Do Now (Part II): Write formulas for Write names for Magnesium Sulfide
Carbon Dioxide
Sodium Phosphite
Copper(II) Nitrite
Write names for
5. NaClO3
6. N2O5
7. K2CrO4
8. SnO2
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

4. Do Now: Write formulas for Write names for Magnesium Sulfide - MgS
Carbon Dioxide - CO2
Sodium Phosphite – Na3PO3
Copper(II) Nitrite – Cu(NO2)2
Write names for
5. NaClO3 – Sodium Chlorate
6. N2O5 – Dinitrogen Pentoxide
7. K2CrO4 – Potassium Chromate
8. SnO2 – Tin(IV) Oxide
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

5. Molecules and Molecular Compounds
Covalent bond: a bond in which atoms are held together through the sharing of electrons
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

6. Molecules and Molecular Compounds
Molecule: neutral group of atoms joined by covalent bonds
H2O - water
C4H10 - butane
C7H5N3O6 – trinitrotoluene (TNT)
Molecular formula - shows how many atoms of each element a molecule contains
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

7. Do Now: Write formulas for Write names for Diphosphorous Pentoxide
Calcium Chloride
Sodium Phosphate
Iron(II) Sulfate
Write names for
5. Na2CO3
6. PF3
7. AlCl3
8. CoBr2
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

8. Do Now: Write formulas for Write names for
Diphosphorous Pentoxide – P2O5
Calcium Chloride - CaCl2
Sodium Phosphate – Na3PO4
Iron(II) Sulfate – FeSO4
Write names for
5. Na2CO3 – Sodium Carbonate
6. PF3 – Phosphorous Trifluoride
7. AlCl3 – Aluminum Chloride
8. CoBr2 – Cobalt(II) Bromide
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

9. The Octet Rule in Covalent Bonding
How many total valence electrons are in the following molecules?
SiO2
HCl
H2O
HCN
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

10. The Octet Rule in Covalent Bonding
Single Covalent Bond: atoms held together by sharing one pair of electrons
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

11. The Octet Rule in Covalent Bonding
Structural Formula: represents covalent bonds as dashes and shows arrangement of covalently bonded atoms.
H:H H-H
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

12. The Octet Rule in Covalent Bonding
Double Covalent Bond: bond that involves two shared pairs of electrons
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

13. The Octet Rule in Covalent Bonding
Triple Covalent Bond: a bond formed by sharing three pairs of electrons
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

14. Bond Dissociation Energies
Bond Dissociation Energy: energy required to break the bond between two covalently bonded atoms.
Bond
Bond Dissociation Energy
(kJ/mol)
Bond Length
(pm)
C C
347
154
C = C
657
133
908
121
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

15. Molecules and Molecular Compounds
Diatomic molecule - molecule that contains two atoms.
HOFBrINCl
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

16. The Octet Rule in Covalent Bonding
Draw Lewis Structures for:
SiO2
HCl
H2O
HCN
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

17. The Octet Rule in Covalent Bonding
Drawing Lewis Dot Structures:
Determine # of valence e-
Determine # of “octet” e-
*Note*– Hydrogen gets 2
# bonds = (# valence e- - # octet e-) / 2
Arrange atoms with # bonds from step 3.
Least electronegative element tends to be in the center
Hydrogen & halogens - bond 1 time (on outside)
Group 6A - bond 2 times
Group 5A - bond 3 times
Carbon - bond 4 times
Add e- until all atoms have correct number of e-
Recheck! Make sure have correct # of e-!
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

18. Coordinate Covalent Bonds
Coordinate Covalent Bond: bond in which one atom contributes both bonding electrons
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

19. Exceptions to the Octet Rule
Total number of valence electrons is an odd number.
2. Boron wants 6 electrons for neutral molecules.
3. Phosphorus and sulfur expand the octet to 10 or 12 electrons.
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

20. Ozone has two possible electron dot structures.
Resonance
Resonance structures: structures that occur when it is possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion.
Ozone has two possible electron dot structures.
Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.