Activity: Building Molecular Models
Unit: Organic Chemistry
For each of the following substances:
a) Draw an electron dot diagram. b) Construct a model using the kits provided.
c) Using your model as a guide, draw a 3-D diagram for the starred compounds.
1. * propane
2. * propene
3. * propyne
4. 1-butene
5. 2-butene
6. 2-methylbutane
7. 2,3-dimethylbutane
8. * propadiene
9. * butadiene (2 ways)
10. cyclobutane
11. * cis-1,2-dimethylcyclobutane
12. 1,3-cyclopentadiene
13. * cis-2-butene
14. * trans-2-butene
15. 3-ethyl-2-pentene
16. * 1,3,5-cyclohexatriene
Questions:
1. Define the following:
a) saturated hydrocarbon
b) unsaturated hydrocarbon
c) straight chain
d) branched chain
e) carbon ring
f) isomer
g) geometric isomers, cis-trans isomers
h) benzene (include a diagram)
2. Draw the electron dot diagrams for each of the following. The name given is incorrect.
Determine the correct name for each of the following.
a) 1,2-dimethylethane
f) 2-methyl-3-propylbutane
b) 2,3,3-triethylpentane
g) 3-propyl-1-pentene
c) 5-hexene
h) 2-ethyl-4-pentene
d) 2,4,6-trimethylhexane
i) 2-propyl-3-methyl-1-propene
e) 2,7-dipropyloctane
j) 3,3-dimethyl-5-heptyne
3. We learned that the general formula for alkanes is CnH2n+2. What is the general formula for
a) alkenes? b) alkynes?
4. Using the models you built in #2 and #3
a) What do you notice about the shape of the six atoms involved in and around a double bond?
b) What do you notice about ht shape of the four atoms involved in and around a triple bond?
c) Do you think that this is important to the molecules reactivity?
5. Explain two common mistakes that could be made while writing names for compounds from
the structure.