1. Chapter Eight: Covalent Bonding
Chemistry 111/112
Chapter Eight: Covalent Bonding

2. Molecular Compounds
So far, we have looked at ionic compounds – composed of a metal and nonmetal, bound together by an ionic bond (electron transfer)
Another type of compound exists that does not exhibit the same properties as ionic compounds
Molecular compounds are composed of nonmetals and share electrons between two nuclei
These shared electrons form a covalent bond

4. Molecules
A molecule is a neutral group of atoms joined together by covalent bonds
The simplest kind of molecules are diatomic – those consisting of two identical nonmetals
O2, Br2, Cl2
A compound composed of molecules is called a molecular compound
Their physical properties include lower melting points and boiling points than ionic compounds

6. Molecular Formulas
A molecular formula is the chemical formula of a molecular compound
It shows how many atoms of each element a molecule contains
Ex. H2O, CO2, CCl4
The subscripts are not necessarily the lowest whole- number ratios

9. Molecular Structure
The formula does not give any indication of its physical structure
Diagrams and models can be used to help illustrate the way in which such compounds arrange themselves
Figure 8.5, p. 215

10. True or False
All molecular compounds are composed of atoms of two or more different elements.
All compounds contain molecules.
No elements exist as molecules.
Most molecular compounds are composed of two or more nonmetallic elements.
Atoms in molecular compounds share electrons.
Molecular compounds tend to have higher melting points and boiling points than ionic compounds.

11. Identify the substance that does not exist.
Br2, KBr, CH4, SO3, N2H2, Ne2
Identify the substance that does not exist.
Identify the ionic compound.
Which formulas represent molecules?
Which formulas represent compounds?
How many atoms are in SO3?

12. For Tuesday, November 5th
Quiz on Chapter 7
Guided reading for Section 8.1
Questions 3 – 6, pg. 216
Section Review 8.1 (due tomorrow at the end of class)