CHEMISTRY
Name_______________
Date ________ Period __
Lab: Molecular Models
Introduction:
Lewis electron dot structures and molecular models are useful ways to visualize the
bonding in molecules. All of the models will follow the octet rule. Exceptions to the octet
rule are hydrogen and helium, since each atom can hold only two valence electrons. Thus,
hydrogen and helium follow the duet rule.
Purpose:
 to become familiar with the three-dimensional shapes of molecules.
 to draw electron dot diagrams for simple and complex molecules.
 to build molecular models from electron dot diagrams.
Prelab: Write your answers in your lab notebook.
1. Draw electron dot diagrams for elements 1 through 18.
2. Draw electron dot structures for the following molecules.
a.
b.
c.
d.
e.
hydrogen gas, H2
water, H2O
oxygen gas, O2
methane, CH4
nitrogen gas, N2
Materials:
molecular model kit
gum drop candies
miniature marshmallows
toothpicks
Safety: Do not eat lab materials! Do not put toothpicks in the eyes or mouth!
Procedure:
Part I: Molecular Model Kit
1. Using the molecular model kit, build models of the five molecules listed in the
prelab: hydrogen gas, water, oxygen gas, methane, and nitrogen gas.
2. Draw a sketch of the model in your lab notebook.
3. Show each model to the instructor for approval before disassembling.
Part II: Candy Creations
1. Draw Lewis structures for the following molecules:
a.
b.
c.
d.
e.
f.
g.
h.
CH2Cl2
Cl2
HOCl
NH3
OHH 3O +
NH4+
SO42-
i.
j.
k.
l.
m.
n.
o.
p.
C2H6
CO2
H 2O 2
C2H4
SO2
SiH4
PH3
O3
q.
r.
s.
t.
u.
v.
HCN
CH3F
CH2O
CO32H 2S
C2H5OH
2. Collect gumdrops, marshmallows, and toothpicks. The gum drop candies and
marshmallows will be used to represent individual atoms. Toothpicks will be used to
represent single bonds, or a pair of shared electrons. Double bonds will require two
toothpicks, and triple bonds will require three toothpicks.
3. Build models of molecules a, d, i, j, q, and v listed above.
4. Show each model to the instructor for approval before disassembling.
Part III: Extension (optional)
Choose one of the following:
1. Select one of the following molecules and build a model. You may use the materials
provided, or choose your own.
ibuprofen, C13H18O2
acetaminophen, C8H9NO2
aspirin, C9H8O4
2. Research (textbook, internet, etc) and select your own molecule to build (must
contain at least 8 atoms). You may use the materials provided, or choose your own.