Download 5. Use your phone to take a picture of each completed model. Put it

9.1 THE MOLECULE MODELING ASSIGNMENT
This exercise goes with Section 9.1 in the text titled Carbon Compounds (starting on page 262). This section is
being added in to Unit 6 as an extension on the concept of covalent bonding.
1.
Before starting to build models obtain one of each color of models and study them so that you may fill out
the chart laying (Titled: WHAT ATOMS DO THE COLORED SPHERES REPRESENT?)out which each model
piece represents. (Once you have completed this and have your work checked you will receive a full set
model kit.)
2. Before building your models, complete the columns “Total Outer Electrons” and “Lewis Structure” in the
data sheet. (HINT: You’ll need to refer to a Periodic Table.)
3. Build models for each of the molecules listed on the data sheet.
a. Gather the kind and number of atoms required. (For example, to make the CH4 molecule you will
need one C and H
b. To determine how many sticks (pairs of electrons) you will need, refer to your Lewis structure
and notice if the bonds are single, double, or triple.
c. Assemble the model by connecting the balls and sticks to match the arrangement in your Lewis
structure.
4. Use the models to fill in the information in the last column “Geometry”. You should take time to think about
(and write down in words and a diagram) the shape of each molecule before proceeding to the next one. If
you have questions, ask your instructor or teaching assistant for help.
5. Use your phone to take a picture of each completed model. Put it on a piece of white paper
for a good photo background.
IN YOUR LAB JOURNAL : Enter the following in your lab journal
 TABLES – Include all tables completed
 QUESTIONS – Include the questions with answers.
 PHOTOS : Include a photo of each molecule you build with a title telling the name of the molecule
and the chemical formula.
Questions to be Answered After Completing the Models
1.
2.
3.
4.
The tetrahedral shape is one of the most fundamental shapes in chemical compounds. Describe it in
words to someone who has not seen it?
The “octet” rule appears to be a very important rule governing the structures of molecules. In light of
your work with models, provide a simple explanation for the importance of 8 electrons.
As a test of what you have learned from this exercise, predict and draw the shapes of (a) NF3 (b) H2S
(c) Cl2O.
Models do not necessarily have to be physical objects. They can be 2-dimensional drawings or even
mental constructs. Cite one or more examples of such models encountered outside of chemistry. Can
you think of models that are used in another field of study ? (Please come up with your own, there are
thousands)
LAST NAME____________________________
Each student must reproduce this into their lab journal.
Determine which atom (or atoms) the colored spheres represent and explain why. (You must complete this
before moving on)
TAKE ONE OF EACH COLOR SPHERE IN A CUP TO YOUR STATION
WHAT ATOMS DO THE COLORED SPHERES REPRESENT?
Colors
Sketch of the Sphere
Which atoms does this
represent?
Describe how your justification for
the atom this represents.
Black
White
Red
Orange
Yellow
Green
HAVE YOUR WORK CHECKED TO THIS POINT BEFORE MOVING ON:___________
Molecule
Total Outer
Electrons
Lewis Structure
Geometry of the Atoms*
Describe the general shape
Hydrogen Gas
H2
Oxygen Gas
O2
Nitrogen
N2
Methane
CH4
SiH4
CF2Cl2
Ammonia
NH3
Water
H2O
Carbon Dioxide
CO2
8 electrons
from the 4
pairs shared.
Be careful, its not what you think, do
some research on this shape.
HAVE YOUR WORK CHECKED TO THIS POINT BEFORE MOVING ON:___________
The alkanes are a class oF chemicals that are created by chains of carbons with single bonds and hydrogens
surrounding the carbon atoms. These can be very long. The names of the Alkanes start with a prefix indicating
the length of the carbon chain followed by –ANE. Example: Methane, stands for the Alkane with a single
carbon in the chain. Below is a list of the prefixes you will work with.
Meth = 1
Pent = 5
Eth = 2
Hex = 6
Prop = 3
Hept = 7
But = 4
Oct = 8
Complete the table below. Build each molecule and be sure to get a photo with the name of the molecule.
Name # of C in
Formula
Lewis Structure
Shape
chain
Methane
(1)
CH4
(2)
C2H6
(3)
(4)
(5)
A pattern exists between the number of Carbons in an Alkane chain and the number of Hydrogen atoms
required to use up all the bonds. This pattern will lead to a general formula for all alkanes. See if you can find
this. If the number of Carbons is n, then how many Hydrogens are needed? (If you can answer this you can
complete the General formula for an Alkane)
HAVE YOUR WORK CHECKED TO THIS POINT BEFORE MOVING ON:___________
Alcohols – Alcohols are a class of chemicals that include a
carbon chain attached to a hydroxide ion (OH-). The diagrams
to the right show 3 ways of showing the alcohol named
methanol (meth means one Carbon). There are thousands of
alcohols but only one can be consumed by people, that one is
called ethanol. The naming of alcohols is similar to that of the alkanes. The prefixes used for the alkanes are
used the same as the alcohols and the names end with –ANOL.
Complete the table below. Build each molecule and be sure to get a photo with the name of the molecule.
Name # of C in
Formula
Lewis Structure
Shape
chain
Methanol
(1)
CH3OH
Ethanol
(2)
C2H5OH
Propanol
(3)
Butanol
(4)
Pentanol
(5)
Can you figure out the general formula for an alcohol? Give it a try.
HAVE YOUR WORK CHECKED TO THIS POINT BEFORE MOVING ON:___________