LD Lewis
Name_________________________
Dot
Molecules notes
In this activity you will use nonmetals to create molecules by sharing their valence electrons to create an
octet.
Guidelines for Drawing Lewis Dot Structures for Molecules:
1. Find out how many valence electrons are on each
atom involved. Example: CO2
5. Place the remaining elements around the central
atom and pairing up the remaining ve- (step 4).
2. Put the atom which is listed first in the molecular
formula – central atom- in the center. HYDROGEN is
NOT a central atom
3. Place 8 valence electrons around this atom- subtract
it from the valence electron total (step 1).
4. Divide the remaining number valence electrons
among the remaining elements.
6. Circle each atom to check IF it has an octet. If not,
move spare/lone pairs electrons into the zone of
sharing.
7. Check that each element has an octet. Change
SHARED PAIRS into lines.
Dihydrogen monoxide
Carbon tetrahydride
Nitrogen trihydride
Carbon disulfide
Carbon monoxide
Nitrogen gas
Name_________________________
Exceptions to the Octet Rule
What are the three reasons for the octet exceptions?
1.
2.
3.
For the following activity, provide the Lewis Dot AND draw the 3 dimensional structures of the
molecule use colors for different elements!
1.
Construct a hydrogen gas molecule. This consists of 2
hydrogen atoms. Chemical formula ___________
Lewis Dot
3-D Model with color
3. Construct a water molecule. This consists of 2 hydrogen
atoms and 1 oxygen atom. Chemical formula ___________
Lewis Dot
3-D Model with color
2. Construct a chlorine gas molecule. This consists of 2
chlorine atoms. Chemical formula ___________.
Lewis Dot
3-D Model with color
4. Construct an ammonia molecule. This consists of 3
hydrogen atoms and one nitrogen atom.
Chemical formula________
Lewis Dot
3-D Model with color
5. Construct a methane gas molecule. This consists of 1 carbon
atom and 4 hydrogen atoms. Chemical formula ___________
6. Construct an ethane molecule. This consists of 2 carbon
atoms and 6 hydrogen atoms. Chemical formula ___________
Lewis Dot
Lewis Dot
3-D Model with color
3-D Model with color
7. Construct a oxygen gas. This consists of 2 oxygen atoms
AND 2 longer flex bonds. Chemical formula ___________
8. Construct a carbon dioxide molecule. This consists of 1
carbon atom and 2 oxygen atoms and 4 flex bonds.
Chemical formula ___________
Lewis Dot
Lewis Dot
3-D Model with color
3-D Model with color
8. Construct a nitrogen gas molecule. This consists of 2
nitrogen atoms and 3 flex bonds. Chemical formula
___________
9. Construct an ethene molecule. This consists of 2 carbon
atoms and 4 hydrogen atoms and 2 flex bonds.
Chemical formula ___________
Lewis Dot
Lewis Dot
3-D Model with color
Post Lab Question
1.
What do the number of holes represent?
3-D Model with color
2.
3.
When you made molecules, it was important to fill
all of the open holes. What would an open hole in a
molecule represent?
Draw a Lewis Dot Diagram for ammonia (again).
Using your Lewis dot diagram, explain why your
molecular model for ammonia looked like it did. Use
the terms “paired electrons” and “unpaired
electrons” in your answer.