Atoms and Molecules
Exploration
CH3
H3C
C
C
H
H2
C
CH3
C
H2
C
C
H
H2
C
OH
Atoms and Molecules
Exploration
CH3
H3C
C
C
H
H2
C
CH3
C
H2
C
C
H
H2
C
OH
Lets Play Octet
Atoms and Molecules Exploration; Page 2
Lets Play Octet
Atoms and Molecules Exploration; Page 2
Atomic Tiles:
Lets Build
Molecules!
Atoms and Molecules Exploration; Page 3
Atomic Tiles:
Lets Build
Molecules!
Atoms and Molecules Exploration; Page 3
Quick Facts:
Atoms are nature’s building blocks. Everything around you, from the shoes on
your feet to the air in this room, is made of atoms. In this activity we are going to
explore how atoms come together to form molecules. To understand how atoms
form bonds we have to understand a little bit about the structure of atoms. An
atom has a dense inner core called the Nucleus that contains protons and neutrons.
It has a squishy outer area that contains electrons called an Electron Cloud. Most
chemical properties of atoms, including how atoms bond to one anther, are the
result of the outermost electrons in the “electron cloud” known as the Valence
Electron. Atomic tiles depict valence electrons as valence electrons as open or
closed circles. Open Circles are electrons that are shared to form bonds. Closed
Circles are electrons that are not shared.
Atoms and Molecules Exploration; Page 4
Quick Facts:
Atoms are nature’s building blocks. Everything around you, from the shoes on
your feet to the air in this room, is made of atoms. In this activity we are going to
explore how atoms come together to form molecules. To understand how atoms
form bonds we have to understand a little bit about the structure of atoms. An
atom has a dense inner core called the Nucleus that contains protons and neutrons.
It has a squishy outer area that contains electrons called an Electron Cloud. Most
chemical properties of atoms, including how atoms bond to one anther, are the
result of the outermost electrons in the “electron cloud” known as the Valence
Electron. Atomic tiles depict valence electrons as valence electrons as open or
closed circles. Open Circles are electrons that are shared to form bonds. Closed
Circles are electrons that are not shared.
Atoms and Molecules Exploration; Page 4
Valence Electrons:
• Outermost electrons of an atom.
• Play a role in forming bonds.
• Determine chemical properties.
• Open and Closed on Atomic Tiles.
Core Electrons:
• Do not play role in bonding.
• Not shown on Atomic Tiles.
We are going to explore covalent bonding. Covalent bonds are formed when
atoms share valence electrons. Shared valence electrons count towards filling the
valence shell for both atoms participating in the bond. It turns out that having a
filled valence shell with 8 electrons is particularly stable. This is known as the
octet rule and it helps Chemists predict how certain atoms and molecules will
react.
Atoms and Molecules Exploration; Page 5
Valence Electrons:
• Outermost electrons of an atom.
• Play a role in forming bonds.
• Determine chemical properties.
• Open and Closed on Atomic Tiles.
Core Electrons:
• Do not play role in bonding.
• Not shown on Atomic Tiles.
We are going to explore covalent bonding. Covalent bonds are formed when
atoms share valence electrons. Shared valence electrons count towards filling the
valence shell for both atoms participating in the bond. It turns out that having a
filled valence shell with 8 electrons is particularly stable. This is known as the
octet rule and it helps Chemists predict how certain atoms and molecules will
react.
Atoms and Molecules Exploration; Page 5
ACTIVITY 1: Lets Make Molecules
Atoms share Valence electrons to form bonds. On Atomic Tiles, Open Circles
depict Bonding valence electrons that do form bonds and Closed Circles depict
Non-bonding valence electrons that do not form bonds.
Warm Up:
Given your observations of Hydrogen, Carbon and Oxygen, lets make a few
predictions.
Which element likely forms the MOST bonds?
Which element likely forms the FEWEST bonds?
Atoms and Molecules Exploration; Page 6
ACTIVITY 1: Lets Make Molecules
Atoms share Valence electrons to form bonds. On Atomic Tiles, Open Circles
depict Bonding valence electrons that do form bonds and Closed Circles depict
Non-bonding valence electrons that do not form bonds.
Warm Up:
Given your observations of Hydrogen, Carbon and Oxygen, lets make a few
predictions.
1.) Which element likely forms the MOST bonds?
2.) Which element likely forms the FEWEST bonds?
Atoms and Molecules Exploration; Page 6
Use your Atomic Tiles to make:
1.) H2O (Water)
(Water has 2 H atoms and 1 O atom… hence H2O)
2.) O2 (Molecular Oxygen)
(Molecular Oxygen has 2 O atoms… hence O2)
Follow ups:
1.) Are the Oxygen tiles the same in both molecules? Yes No
2.) Add dots to the blank tiles below. Use your observations to fill out the table.
Oxygen
Open Circles
Closed Circles
Valence Electrons
What things are the same for each oxygen tile?
What things are different from one tile to another?
Atoms and Molecules Exploration; Page 7
Use your Atomic Tiles to make:
1.) H2O (Water)
(Water has 2 H atoms and 1 O atom… hence H2O)
2.) O2 (Molecular Oxygen)
(Molecular Oxygen has 2 O atoms… hence O2)
Follow ups:
1.) Are the Oxygen tiles the same in both molecules? Yes No
2.) Add dots to the blank tiles below. Use your observations to fill out the table.
Oxygen
Open Circles
Closed Circles
Valence Electrons
What things are the same for each oxygen tile?
What things are different from one tile to another?
Atoms and Molecules Exploration; Page 7
Bonding Pause…
When we match open circles using atomic tiles we are showing which valence
electrons are shared to form bonds.
Match
single dots
double dots
triple dots
Bonds
1
2
3
Name
Single Bond
Double Bond
Triple Bond
Electrons Shared
2
4
6
Valence electrons shared in a bond count towards filling the valence shell for both
atoms participating in the bond.
To count the total number of valence electrons around an atom after bonding we
add the number of shared electrons to the number of nonbonding electrons.
Total Valence Electrons
= Shared Electrons + Non Bonding Electrons
After Bonding


Open Circles
Closed Circles
Atoms and Molecules Exploration; Page 8
Bonding Pause…
When we match open circles using atomic tiles we are showing which valence
electrons are shared to form bonds.
Match
single dots
double dots
triple dots
Bonds
1
2
3
Name
Single Bond
Double Bond
Triple Bond
Electrons Shared
2
4
6
Valence electrons shared in a bond count towards filling the valence shell for both
atoms participating in the bond.
To count the total number of valence electrons around an atom after bonding we
add the number of shared electrons to the number of nonbonding electrons.
Total Valence Electrons
= Shared Electrons + Non Bonding Electrons
After Bonding


Open Circles
Atoms and Molecules Exploration; Page 8
Closed Circles
Use your Atomic Tiles to make:
A.) NH3 (Ammonia)
B.) HCN (Hydrogen Cyanide)
C.) N2 (Molecular Nitrogen)
D.) HNO (Nitroxyl)
Follow ups:
1.) Are the Nitrogen tiles the same in all the molecules? Yes No
2.) What things are different from one tile to another?
3.) How many Valence Electrons does Nitrogen have?
4.) Fill in the Bonding table below for each Nitrogen Atomic Tile.
Nitrogen
Single bonds
Double bonds
Triple bonds
Total Valence Electrons
3
0
0
8
Atoms and Molecules Exploration; Page 9
Use your Atomic Tiles to make:
A.) NH3 (Ammonia)
B.) HCN (Hydrogen Cyanide)
C.) N2 (Molecular Nitrogen)
D.) HNO (Nitroxyl)
Follow ups:
1.) Are the Nitrogen tiles the same in all the molecules? Yes No
2.) What things are different from one tile to another?
3.) How many Valence Electrons does Nitrogen have?
4.) Fill in the table below for each Nitrogen Atomic Tile.
Nitrogen
Single bonds
Double bonds
Triple bonds
Total Valence Electrons
3
0
0
8
Atoms and Molecules Exploration; Page 9
Use your Atomic Tiles to make:
A.) CO2 (Carbon Dioxide)
B.) C2H6 (Ethane)
C.) C2H4 (Ethene)
D.) C2H2 (Ethyne)
Follow ups:
1.) Are the Carbon tiles the same in all the molecules? Yes No
2.) What things are different from one tile to another?
3.) How many bonds does Hydrogen make?
4.) Fill in the table below for each Carbon Atomic Tile.
Nitrogen
Single bonds
Double bonds
Triple bonds
Total Valence Electrons
4
0
0
8
Atoms and Molecules Exploration; Page 10
Use your Atomic Tiles to make:
A.) CO2 (Carbon Dioxide)
B.) C2H6 (Ethane)
C.) C2H4 (Ethene)
D.) C2H2 (Ethyne)
Follow ups:
1.) Are the Carbon tiles the same in all the molecules? Yes No
2.) What things are different from one tile to another?
3.) How many bonds does Hydrogen make?
4.) Fill in the table below for each Carbon Atomic Tile.
Nitrogen
Single bonds
Double bonds
Triple bonds
Total Valence Electrons
4
0
0
8
Atoms and Molecules Exploration; Page 10
1.) Which element forms the MOST bonds?
2.) Which element forms the FEWEST bonds?
3.) Where does Nitrogen fit in the above comparisons?
4.) Did you see any trend in the Total Number Valence Electrons for Carbon and
Nitrogen when all of their dots are matched?
5.) Can you guess why the Atomic Tile game is named Octet?
Atoms and Molecules Exploration; Page 11
1.) Which element forms the MOST bonds?
2.) Which element forms the FEWEST bonds?
3.) Where does Nitrogen fit in the above comparisons?
4.) Did you see any trend in the Total Number Valence Electrons for Carbon and
Nitrogen when all of their dots are matched?
5.) Can you guess why the Atomic Tile game is named Octet?
Atoms and Molecules Exploration; Page 11
Periodic Pause:
➠
Atoms and Molecules Exploration; Page 12
Periodic Pause:
➠
Atoms and Molecules Exploration; Page 12
Quick Facts: The Periodic Table
The development of the periodic table is a triumph of critical thinking and careful
observation. In the late 1800’s chemists struggled to find coherence among the
chemical and physical properties of elements. While many scientists worked on
this problem, Dmitri Mendeleev, a Russian high school chemistry teacher in the
late 1800’s, is credited with envisioning the modern periodic table in his 1868
textbook, “Principles of Chemistry”. His approach to organizing the known
elements stood the test of time as much for what it did not include as for what it
did include. Confident in his organizational structure, Mendeleev left several gaps
in his periodic table that accurately predicted future elemental discoveries.
Atoms and Molecules Exploration; Page 13
Quick Facts: The Periodic Table
The development of the periodic table is a triumph of critical thinking and careful
observation. In the late 1800’s chemists struggled to find coherence among the
chemical and physical properties of elements. While many scientists worked on
this problem, Dmitri Mendeleev, a Russian high school chemistry teacher in the
late 1800’s, is credited with envisioning the modern periodic table in his 1868
textbook, “Principles of Chemistry”. His approach to organizing the known
elements stood the test of time as much for what it did not include as for what it
did include. Confident in his organizational structure, Mendeleev left several gaps
in his periodic table that accurately predicted future elemental discoveries.
Atoms and Molecules Exploration; Page 13
Find elements that have the Same Number of Valence Electrons as each of the
following. Sketch an example in the box below.
Same Number of Valence Electrons
Elements with the Same Number of Valence Electrons are said to be in the same
“Family”. Why might that be?
Atoms and Molecules Exploration; Page 14
Find elements that have the Same Number of Valence Electrons as each of the
following. Sketch an example in the box below.
Same Number of Valence Electrons
Elements with the Same Number of Valence Electrons are said to be in the same
“Family”. Why might that be?
Atoms and Molecules Exploration; Page 14
Set the Table:
Create a mini-periodic table with atomic tiles. Using atomic numbers and valence
electrons, recreate the first three rows of the periodic table.
Given the matches you made above, do Elemental Families run from right to left
(horizontal) or from top to bottom (vertical)?
Bonding:
Elements in a family tend to have very similar chemical properties. What bonding
trends do you see amongst elements in the…
1. Carbon Family:
2. Nitrogen Family (pnicogens):
3. Oxygen Family (chalcogens):
4. Fluorine Family (halogens):
Atoms and Molecules Exploration; Page 15
Set the Table:
Create a mini-periodic table with atomic tiles. Using atomic numbers and valence
electrons, recreate the first three rows of the periodic table.
Given the matches you made above, do Elemental Families run from right to left
(horizontal) or from top to bottom (vertical)?
Bonding:
Elements in a family tend to have very similar chemical properties. What bonding
trends do you see amongst elements in the…
5. Carbon Family:
6. Nitrogen Family (pnicogens):
7. Oxygen Family (chalcogens):
8. Fluorine Family (halogens):
Atoms and Molecules Exploration; Page 15
Predictions:
Using your mini- periodic table, and a realtm periodic table predict how many
valence electrons each of the following likely have.
Selenium (Se)_______
Iodine (I)_______
Radon (Ra) _______
Draw lines to match elements with the same number of valence electrons.
Carbon (C)
Aluminum (Al)
Cesium (Cs)
Lead (Pb)
Indium (In)
Argon (Ar)
Sulfur (S)
Potassium (K)
Nitrogen (N)
Atoms and Molecules Exploration; Page 16
Predictions:
Using your mini- periodic table, and a realtm periodic table predict how many
valence electrons each of the following likely have.
Selenium (Se)_______
Iodine (I)_______
Radon (Ra) _______
Draw lines to match elements with the same number of valence electrons.
Carbon (C)
Aluminum (Al)
Cesium (Cs)
Lead (Pb)
Indium (In)
Argon (Ar)
Sulfur (S)
Potassium (K)
Nitrogen (N)
Atoms and Molecules Exploration; Page 16
Lewis Structures:
Environmental Puzzles
➠
Atoms and Molecules Exploration; Page 17
Lewis Structures:
Environmental Puzzles
➠
Atoms and Molecules Exploration; Page 17
Lewis Dot Structures
Let’s try to translate these puzzles onto paper.
Bonds:
Single Dot Match => Single bond… Single line between atoms
Double Dot Match => Double bond… Double line between atoms
Triple Dot Match => Triple bond… Triple line between atoms
Lone Pairs:
Non-bonding electrons => lone pairs… two dots
e.g. Formaldehyde CH2O
➠
Atoms and Molecules Exploration; Page 18
Lewis Dot Structures
Let’s try to translate these puzzles onto paper.
Bonds:
Single Dot Match => Single bond… Single line between atoms
Double Dot Match => Double bond… Double line between atoms
Triple Dot Match => Triple bond… Triple line between atoms
Lone Pairs:
Non-bonding electrons => lone pairs… two dots
e.g. Formaldehyde CH2O
➠
Atoms and Molecules Exploration; Page 18
Quick Facts: Greenhouse Gases
Scientists estimate that given the amount of solar energy reaching the Earth, our planet
should have an average surface temperature of ~ - 45°C. In actuality, the average
surface temperature on Earth is closer to 20°C. Greenhouse gases play a central role in
maintaining our hospitable climate and like many things, too much of a “good thing”
can lead to trouble. Greenhouse gases are a family of molecules that absorb light in the
infrared. In the absence of greenhouse gases, light reflected from the Earth’s surface
(and the energy it carries) would be lost to space. With greenhouse gases, a fraction of
the light energy reflected from the Earth’s surface is absorbed and re-emitted back
down to Earth.
Name
Water
Carbon Dioxide
Methane
Freon-11:
Formula
H2 O
CO2
CH4
CCl3F
Atoms and Molecules Exploration; Page 19
Quick Facts: Greenhouse Gases
Scientists estimate that given the amount of solar energy reaching the Earth, our planet
should have an average surface temperature of ~ - 45°C. In actuality, the average
surface temperature on Earth is closer to 20°C. Greenhouse gases play a central role in
maintaining our hospitable climate and like many things, too much of a “good thing”
can lead to trouble. Greenhouse gases are a family of molecules that absorb light in the
infrared. In the absence of greenhouse gases, light reflected from the Earth’s surface
(and the energy it carries) would be lost to space. With greenhouse gases, a fraction of
the light energy reflected from the Earth’s surface is absorbed and re-emitted back
down to Earth.
Name
Water
Carbon Dioxide
Methane
Freon-11:
Formula
H2 O
CO2
CH4
CCl3F
Atoms and Molecules Exploration; Page 19
Sketch a Lewis structure for each molecule in the space provided.
H2O
CO2
CH4
Atoms and Molecules Exploration; Page 20
Sketch a Lewis structure for each molecule in the space provided.
H2O
CO2
CH4
Atoms and Molecules Exploration; Page 20
Quick Facts: Ozone Layer
Most oxygen in our atmosphere is diatomic O2. Ozone, O3, is a relatively unstable
triatomic allotrope of oxygen. In troposphere (near the Earth’s surface) ozone is a
pungent pollutant. It irritates the eyes and has many harmful effects on the
respiratory system. In the stratosphere, 10-50 km from the surface of the Earth,
ozone plays a completely different role. It acts as Earth’s “Sun Screen”. It absorbs
a substantial fraction of the high-energy ultraviolet (UV) light entering Earth’s
atmosphere that is harmful to life on our planet.
Make O2 and O3 with your cards and sketch Lewis structure.
O2
O3
Atoms and Molecules Exploration; Page 21
Quick Facts: Ozone Layer
Most oxygen in our atmosphere is diatomic O2. Ozone, O3, is a relatively unstable
triatomic allotrope of oxygen. In troposphere (near the Earth’s surface) ozone is a
pungent pollutant. It irritates the eyes and has many harmful effects on the
respiratory system. In the stratosphere, 10-50 km from the surface of the Earth,
ozone plays a completely different role. It acts as Earth’s “Sun Screen”. It absorbs
a substantial fraction of the high-energy ultraviolet (UV) light entering Earth’s
atmosphere that is harmful to life on our planet.
Make O2 and O3 with your cards and sketch Lewis structure.
O2
O3
Atoms and Molecules Exploration; Page 21
Quick Facts: Ozone Depletion
In the late 1920’s a family of compounds, Chlorofluorocarbons (CFC’s), were
developed as refrigerants. Ironically, these non-toxic fairly non-reactive
compounds were developed to replace acutely toxic refrigerants of the time like
ammonia (NH3) and sulfur dioxide (SO2). In 1974 Molina and Rowland showed
CFC’s were responsible for degrading the ozone layer, effectively removing our
“Sun Screen”. Molina and Rowland won the Nobel Prize for Chemistry for this
work in 1995 (one year after the use of CFCs began to be phased out on an
international level).
Name
Freon-11:
Freon-12:
Freon-150:
Formula
CCl3F
CCl2F2
H4C2Cl2
Atoms and Molecules Exploration; Page 22
Quick Facts: Ozone Depletion
In the late 1920’s a family of compounds, Chlorofluorocarbons (CFC’s), were
developed as refrigerants. Ironically, these non-toxic fairly non-reactive
compounds were developed to replace acutely toxic refrigerants of the time like
ammonia (NH3) and sulfur dioxide (SO2). In 1974 Molina and Rowland showed
CFC’s were responsible for degrading the ozone layer, effectively removing our
“Sun Screen”. Molina and Rowland won the Nobel Prize for Chemistry for this
work in 1995 (one year after the use of CFCs began to be phased out on an
international level).
Name
Freon-11:
Freon-12:
Freon-150:
Formula
CCl3F
CCl2F2
H4C2Cl2
Atoms and Molecules Exploration; Page 22
Make each molecule with your cards and sketch Lewis structure.
CCl3F
CCl2F2
H4C2Cl2
Atoms and Molecules Exploration; Page 23
Make each molecule with your cards and sketch Lewis structure.
CCl3F
CCl2F2
H4C2Cl2
Atoms and Molecules Exploration; Page 23
Atomic Puzzles:
What’s That Taste?
O
O
HO
C
OH
C
O
C
C
C
C
H2 OH H2
OH
Atoms and Molecules Exploration; Page 24
Atomic Puzzles:
What’s That Taste
O
O
HO
C
OH
C
O
C
C
C
C
H2 OH H2
OH
Atoms and Molecules Exploration; Page 24
Quick Facts:
Citric acid is one of the molecules that give citrus fruits like oranges, grapefruits and
lemons their tart taste. Citric acid is acidic, it will react with baking soda (NaHCO3) to
form carbon dioxide (CO2) gas.
Taste Test:
1.) Taste each juice.
2.) How do the juices Tartness compare?
Most Tart
Least Tart
>
>
>
Atoms and Molecules Exploration; Page 25
Quick Facts:
Citric acid is one of the molecules that give citrus fruits like oranges, grapefruits and
lemons their tart taste. Citric acid is acidic, it will react with baking soda (NaHCO3) to
form carbon dioxide (CO2) gas.
Taste Test:
1.) Taste each juice.
2.) How do the juices Tartness compare?
Most Tart
Least Tart
>
>
Atoms and Molecules Exploration; Page 25
>
Bubble Test:
1.) Add 1 teaspoon of baking soda to each
cup of juice.
2.) Observe the reaction.
3.) Sketch what you see in each cup.
4.) Rank the Juices based on how many bubbles they produced.
Most Bubbles
>
>
Least Bubbles
>
Atoms and Molecules Exploration; Page 26
Bubble Test:
1.) Add 1 teaspoon of baking soda to each
cup of juice.
2.) Observe the reaction.
3.) Sketch what you see in each cup.
4.) Rank the Juices based on how many bubbles they produced.
Most Bubbles
>
>
Atoms and Molecules Exploration; Page 26
Least Bubbles
>
Conclusion:
Based on your observations, which juice has the most Citric Acid? Which has the
Least?
Most
Citric Acid
Least
Citric Acid
>
>
>
Atomic Puzzle: Citric Acid
O
O
HO
C
OH
C
C
O
C
C
C
C
H2 OH H2
H
O
Formula:
OH
1.) Make a model of Citric Acid using Atomic Tiles. Note some of the hydrogen atoms
may need to overlap.
Atoms and Molecules Exploration; Page 27
Conclusion:
Based on your observations, which juice has the most Citric Acid? Which has the
Least?
Most
Citric Acid
Least
Citric Acid
>
>
>
Atomic Puzzle: Citric Acid
O
O
HO
C
OH
C
C
O
C
C
C
C
H2 OH H2
OH
H
O
Formula:
1.) Make a model of Citric Acid using Atomic Tiles. Note some of the hydrogen atoms
may need to overlap.
Atoms and Molecules Exploration; Page 27
Atoms and Molecules Exploration; Page 28
Atoms and Molecules Exploration; Page 28