1. Chemistry 121/122
isomers

2. Isomers
The prefix “iso-” means same parts. How does this help with the definition of the term isotope?
Some hydrocarbons only differ in their structural arrangement, not their structural formula
Ex. C5H8 has three structural arrangements
When the arrangements are different but the formula is the same, the molecules are referred to as structural isomers
They have different physical characteristics

3. Stereoisomers – Geometric Isomers
Stereoisomers exist when the order of the atoms is identical but their positions in space is different - bond angles are different
Geometric isomers are joined in the same order but differ in the orientation of groups around a double bond
There are two configurations – trans (opposite sides) and cis (same sides)
They are possible whenever each carbon of the double bond has at least one substituent

4. Stereoisomers – Optical Isomers
Optical isomers exist when a carbon atom has four different atoms or groups attached, the molecule is asymmetric
They are mirror images of each other – such as in looking at yourself in the mirror
The mirror images will never be identical unless bonds are broken
Conceptual Problem 22.4

5. For the remainder of class…
Question 25 on page 707
Worksheet
Quick Lab – Page 707
To be passed in Monday
Complete questions 1 – 3 under the analyze and conclude section
Draw and name the nine structural isomers of heptane (C7H16)
Bonus Assignment (add 5 points to your Test), draw and name the 18 isomers of octane – due Monday