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The following instructional plan is part of a GaDOE collection of Unit Frameworks, Performance Tasks, examples of Student
Work, and Teacher Commentary. Many more GaDOE approved instructional plans are available by using the Search Standards
feature located on GeorgiaStandards.Org.
Georgia Performance Standards Framework for Science – Chemistry
Introduction
Exploring Change – Bonds, Energy, and Reactions
Unit Framework Annotation
This unit is designed to build the enduring understanding that atomic structure dictates bonding, which in turn
determines the structure of molecular and ionic compounds, diatomic elements, and allotropes, and that these
structures determine the compounds’ properties. The unit builds on bonding and conservation of mass to begin
the study of patterns of reactions, balancing chemical equations and stoichiometric calculations related to the
reactions. Both manipulatives and traditional lab activities are integral parts of the exploration in this unit.
This unit integrates the understandings from “Finding Order” and “Finding Patterns” to explore how atoms and
ions bond and the changes that occur when bonds are broken or formed.
•
•
•
•
IUPAC conventions for writing formulas and naming compounds are taught.
The mole concept is extended to compounds and balanced equations in this unit.
Stoichiometry is introduced and used to make calculations consistent with the conservation of matter.
Acids and bases are explored as specific categories of compounds.
The instruction, tasks, and assessments in this unit are suggested but should be adjusted, omitted, or enhanced as
needed for specific class situations. Some classes may need more time, practice, or instruction for some concepts.
Others may need less. Fore these reasons, the number of days required may need adjustment.
Approximate Duration for the Unit Framework
5 weeks-variable (Depending on the needs of the students, the actual time needed for practice, informal
assessment, and adjusting instruction may be more than 5 weeks.)
Standards
Focus Content Standards
SC1. Students will analyze the nature of matter and its classifications.
SC1b. Identify substances based on chemical and physical properties.
SC1c. Predict formulas for stable ionic compounds (binary and tertiary) based on balance of charges.
SC1d. Use IUPAC nomenclature for both chemical names and formulas:
• Ionic compounds (Binary and tertiary)
• Covalent compounds (Binary and tertiary)
• Acidic compounds (Binary and tertiary)
SC2. Students will relate how the Law of Conservation of Matter is used to determine chemical
composition in compounds and chemical reactions.
SC2a Identify and balance the following types of chemical equations:
• Synthesis
• Decomposition
• Single Replacement
• Double Replacement
• Combustion
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 1 of 17
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Georgia Performance Standards Framework for Science – Chemistry
SC2b. Experimentally determine indicators of a chemical reaction: specifically precipitation, gas
evolution, water production, and changes in energy to the system.
SC2c. Apply concepts of the mole and Avogadro’s number to conceptualize and calculate
•Empirical/molecular formulas,
•Mass, moles and molecules relationships
SC2d. Identify and solve different types of stoichiometry problems, specifically relating mass to moles
and mass to mass.
SC3. Students will use the modern atomic theory to explain the characteristics of atoms.
SC3e. Compare and contrast types of chemical bonds (i.e. ionic, covalent).
SC7. Students will characterize the properties that describe solutions and the nature of acids and
bases.
SC7b. Compare, contrast, and evaluate the nature of acids and bases:
Integrated Characteristics of Science Standards
SCSh1a Exhibit curiosity, honesty, openness, and skepticism in their own scientific activities.
SCSh2. Students will use standard safety practices for all classroom laboratory and field
investigations.
SCSh3. Students will identify and investigate problems scientifically.
SCSh4. Students will use tools and instruments for observing, measuring, and manipulating
SCSh5. Students will demonstrate the computation and estimation skills necessary for
analyzing data and developing reasonable scientific explanations.
SCSh6a. Write clear, coherent laboratory reports related to scientific investigations.
SCSh6b. Write clear, coherent accounts of current scientific issues, including possible alternative
interpretations of the data.
SCSh8b. Scientific researchers are expected to critically assess the quality of data including
possible sources of bias in their investigations’ hypotheses, observations, data analyses, and
interpretations.
SCSh8e. The ultimate goal of science is to develop an understanding of the natural universe which is
free of biases.
SCSh8f Science disciplines and traditions differ from one another in what is studied, techniques used,
and outcomes sought.
Complementary Standards
SC1b. Identify substances based on chemical and physical properties
SC5. Students will understand the rate at which a chemical reaction occurs can be affected by
changing concentration, temperature, or pressure and the addition of a catalyst
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 2 of 17
Copyright 2006 © All Rights Reserved
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Georgia Performance Standards Framework for Science – Chemistry
Understanding and Goals
Unit Understandings, Themes, and Concepts determines
• A chemical bond is a force holding atoms/ions in a combined state.
• The bond may be ionic or covalent, or may be categorized along a continuum between ionic and
covalent.
• Atomic structure dictates bonding, which in turn determines the structures of compounds (and
diatomic molecules of elements), and structures determine the compounds’ properties.
• In a chemical change, bonds are broken and new bonds are formed, matter is conserved, and energy
is always involved.
• Indicators of chemical change include color change, formation of a precipitate or water, evolution of
a gas, and changes in energy. (See teacher note below.)*
• Most reactions can be described by five basic patterns of reactions.
• Chemical formulas reflect the conservation of matter in bonding and can be determined
experimentally.
*Teacher Note: The same indicators may be observed in numerous physical changes. However,
the important difference here is that the color change, the odor produced, the precipitate formed,
or the gas evolved, results because a new product was formed in the reaction; whereas these
indicators in a physical change result because the same substance is in a different state or
condition. Point out this crucial difference throughout this unit. An example of this would be
that when silver nitrate and sodium chloride react, the products are silver chloride ( a white
precipitate), and sodium nitrate. The new precipitate indicates a chemical reaction. When sand
and water are mixed and agitated, the sand is suspended in the water. Over time the sand settles
(precipitates to the bottom) but it is still sand. This is a physical event.
Students should understand that energy is involved in both physical and chemical changes.
Essential Questions
ƒ What determines how elements are attracted to each other in compounds? How do elements bond?
(What is a chemical bond, anyway?)
ƒ How are properties related to bonding?
ƒ How are formulas written to reflect the composition of compounds?
ƒ How are ionic and molecular compounds named?
ƒ How do groups of atoms form polyatomic ions and why do they act as a single unit when bonding
with other ions?
ƒ How can you tell if a chemical change has taken place? What are indications that chemical reactions
have taken place?
ƒ How are formulas determined experimentally?
ƒ What do glucose, acetic acid, and formaldehyde have in common? (How can you determine if the
molecular formula is a multiple of the empirical formula?)
ƒ Where do acids and bases fit into the organization of compounds?
ƒ How are formulas for acids and bases written and how are they named?
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 3 of 17
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Georgia Performance Standards Framework for Science – Chemistry
Balanced Assessments
Method
types
Informal
Observations
Dialogue and
Discussion
Selected
Responses
Constructed
Responses
Self -Assessments
Monitor progress
during formula
writing practice
Student/teacher
Peer
conferencing
Whole group
discussion
Teacher
prepared items
on quizzes and
summative test
to assess
specific unit
content
Writing: How is
salt different
from sugar?
Practicing mole
conversions
Monitor practice
during mole
conversions
Discuss bonding;
monitor student
understanding
through
questioning
Discussion
during acid/base
lab---check for
understanding
Discuss physical
and chemical
properties;
monitor student
understanding
through
questioning
Graphic
organizer:
properties of
acids & bases
Practicing writing
formulas
Practice balancing
equations
Formula
construction
Ionic/covalent
Properties
Indications of
chemical reaction
lab
Formula of a
hydrate lab
Quizzes on formula
writing/naming,
empirical/
molecular formulas
Formula – mole
conversions
Empirical formula
of magnesium
oxide calculation
Balance equations
identify reactions
Analysis of
reactions task
Unit Performance Assessment(s)
“Water” you thinking? Performance Assessment
Choice One: Write an analytical essay based on the understandings in this unit to explain how
atoms and ions bond. The title alludes to the uniqueness of the bonding in and between water
molecules and should prompt the writer to consider the range of possibilities that exist in bonding.
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 4 of 17
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Georgia Performance Standards Framework for Science – Chemistry
To prepare for writing, review the essential questions and what you know about each. Include the
following topics.
ƒ differences in the properties of ionic and molecular compounds
ƒ how ionic and covalent bonds form
ƒ how electron arrangement affects bonding
ƒ how bonding affects structure
ƒ how structure affects properties
In your essay, use specific examples to support your statements. Also, be careful to use the language
associated with these concepts appropriately.
Choice Two: (This may be used when a differentiated assignment is needed.)
Construct a concept map that illustrates the key points indicated in choice one.
Choice Three: Reactions in a Bag Task
Reactions in a Bag- This task is written up in various laboratory guides and demonstration books. In
this unit, the reaction should be approached as an inquiry activity as a bridge from bonding and formulas
to reactions and equations.
Teacher Procedure:
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Have students complete the DO NOW as described in the lesson.
Establish lab partners or groups.
Have each group’s runner pick up the materials for their group.
Students will need to obtain approximately 5 g. of the NaHCO3 and of the CaCl2. It may be
expedient to have pre-measured the chemicals into small lab containers or into snack size resealable plastic bags for each group.
Review safety with students
The language of chemical reactions should be embedded in the context of this lesson:
reactant, product, endothermic, exothermic, yields.
Student Procedures:
Prelab
ƒComplete DO NOW
ƒReview safety with teacher
ƒEstablish group roles
ƒRunner picks up materials
ƒMake micro-spatulas and ampule (See instructions below.)
Materials :
sodium hydrogen carbonate, 5 g
calcium chloride, 5 g
water, 5 mL
phenol red solution
one zip-top plastic bag
lab scissors
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 5 of 17
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Georgia Performance Standards Framework for Science – Chemistry
™ four disposable pipettes
™ Micro-scale technique: Cut the bulbs of two plastic pipettes at an angle to create micro-spatulas.
Cut the third pipette across stem near where it joins the bulb to make an ampule. The fourth
pipette is for the water.
CUT PIPETTE ALONG DASHED LINE
TO MAKE SPATULA.
CUT PIPETTE ALONG DASHED LINE TO
MAKE AMPULE.
Part I (Teacher note: If Part I was done as part of lesson 13, unit 3, then review by demonstrating it
again for the class. Then proceed with the rest of the lab.)
ƒUsing one of the spatulas, place two scoops of calcium chloride in one corner of the plastic bag.
Using the other micro spatula, place one scoop of sodium hydrogen carbonate in the other
corner, so that the two compounds are not in contact with each other.
ƒFill the ampule with phenol red and place in the plastic bag. Use the remaining pipette to add
approximately 2 mL of water to the bag. (one bulb full of water)
ƒImmediately press the air out of the bag and close it completely.
ƒOnce the bag is sealed, squeeze the ampule of phenol red out into the bag, and mix the four
compounds together.
ƒObserve carefully and record observations that are signs of a chemical change.
Part II
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
Devise a plan for investigating which compounds react to give which results.
Present this plan for approval to the teacher.
Obtain any other equipment required in your plan. (more reactants, bags, pipettes, etc.)
Carry out your approved procedure
Keep careful data on what happens in each case.
Note that the phenol red is a solution of phenol red in water
Post Lab: Students should complete their data table and observations. These should be assessed.
Explain to students that by the end of this unit, they will be able to trace the series of chemical reactions
that actually took place in the bag and explain how atoms and ions were rearranged to produce the final
products.
Teacher note: the purpose here is for the students to mix two of the reactants at a time to see what
happens. The following is a key.
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 6 of 17
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CaCl2 + H2O
NaHCO3 + H2O
CaCl2 +phenol red C19H13O5
NaHCO3+ phenol red C19H13O5
CaCl2 + NaHCO3+ phenol red C19H13O5
Hot
Cold
Hot
Cold
Hot
The reactions described in the following links can be conducted as a mini-lab. Students carry out the
procedures, and record their data. Students must observe all lab safety rules. Data for each reaction
should be recorded and then discussed by the class.
http://www.teamcamelotonline.com/reaction%20in%20a%20bag.pdf
An Endothermic Reaction
Teacher Background Note: The students will notice changes in temperature, the production of a gas,
and the color change.
The word equation is Calcium hydrogen carbonate + Calcium chloride Æ sodium chloride, calcium
carbonate, carbon dioxide, and water.
These products are actually the result of a series of changes, but the summary equation given above
should be used with this lesson.
The summary given below can be used later in this unit after studying the types of reactions.
•
•
•
The dissolving and dissociation of the CaCl2 and NaHCO3
The formation of Ca(HCO3)2 and NaCl from the reactants (double replacement)
The formation of CaCO3, CO2 and H2O from the Ca(HCO3)2 (decomposition)
CaCl2 + 2NaHCO3 ------Æ Ca(HCO3)2 and 2NaCl
Ca(HCO3)2 -------Æ CaCO3, CO2 and H2O
Tie it all together: Throughout this unit, this reaction system can be used to illustrate concepts of
solvation, energy change, gas pressure, and equilibrium. While these concepts will be covered in
greater detail in Unit Four, Exploring Systems, the concepts can be introduced in the context of this
task.
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 7 of 17
Copyright 2006 © All Rights Reserved
One Stop Shop For Teachers
Georgia Performance Standards Framework for Science – Chemistry
Rubric for Performance Task
Rubric for Concept Map: Reaction types
Types of
reactions
Map shows
relationship
between
reactants and
products
correctly and
relationship to
other reaction
types correctly.
Map shows
relationship
between
reactants and
products but
relationship to
other reaction
types is
unclear or
missing.
Reaction
type is
shown, but
relationship
between
reactants
and
products is
unclear;
relationship
to other
reaction
types is
adequate.
Reaction type is
shown but is
unclear, or
incorrect;
relationships to
other reaction
types are
missing.
Reaction
type is
missing.
15 points
12 points
10points
5 points
0 points
Design and
organization of
map indicate a
clear overall
analysis of the
reaction types
and can be
understood
without
additional
explanation.
25 points
Design of the
map indicates
acceptable
understanding
of the reaction
types but not
all parts are
clear.
Necessary
information
is present,
but design of
the map is
hard to
interpret.
Additional
explanation
is needed.
Design indicates
a lack of
understanding of
reaction types.
Re-do and
resubmit for
reassessment
within three
days.
10 points
This is not a
concept
map! Or no
map is
present.
20 points
15 points
Composition
Decomposition
Single
Replacement
Double
Replacement
Combustion
Design of
concept map
Total points
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 8 of 17
Copyright 2006 © All Rights Reserved
Submit
within three
days for
assessment
0 points
One Stop Shop For Teachers
Georgia Performance Standards Framework for Science – Chemistry
Student Work Sample with Teacher Commentary
Web Resources:
ƒ http://ithacasciencezone.com/chemzone/chelinks.htm. This website has a wealth of links and
resources for this unit as well as for other chemistry topics.
ƒ Ionic bonding and properties: Atoms and subatomic particles
ƒ United streaming has several video clips available on chemical reactions (including teacher
guides and black line masters for students).
ƒ www.unitedstreaming.com .Schools/ systems can obtain access and passwords.
ƒ http://www.visionlearning.com/library/x_linker.php?moid=2117&l= This site gives a
comprehensive treatment of the topics in this unit.
ƒ http://www.800mainstreet.com/4/0004-0010-formula-ionic.html for Day 2 and other helps.
ƒ http://www.dhmo.org
ƒ www.cci.unl.edu/Chemistry/DoChem/DoChemKeys.html
ƒ http://129.93.84.115/Chemistry/DoChem/DoChem096.html
ƒ http://www.chemtopics.com/unit02/unit2f.htm
ƒ http://www.thecatalyst.org/
ƒ http://filebox.vt.edu/users/ckeel/lps.htm
ƒ http://www.chemreview.net/download_instructions.htm
Other Resources
ƒ The formula construction materials are available from various chemistry supply companies in
kits, but can be homemade.
ƒ Most lab books have an empirical formula lab, and a formula of a hydrate lab available.
PERFORMANCE TASKS FOR LEARNING AND ASSESSMENT
Properties of Compounds
Give students labeled samples of ionic and covalent compounds. Do not indicate whether they are ionic
or covalent. Some examples include sugar, salt, vinegar, dilute HCl, dilute NaOH, and oil (if you don’t
mind getting messy!).
Student pairs or teams will design procedures for testing and recording data on the properties such as
conductivity, solubility, hardness, brittleness, and melting point.
After teacher approval, students will carry out their procedures, and collect their data.
In order to analyze their data, students should research the general properties of ionic and covalent
compounds. After doing this, each sample should be identified as ionic or covalent.
Students incorporate all these steps into a complete lab report.
Teacher notes:
a. All safety rules must be strictly enforced, including the wearing of goggles and aprons, fire, heat,
and electrical safety, and safe handling of chemicals and glassware. I mini-lesson on some of the
necessary techniques, equipment, and procedures should precede this lab.
b. Conductivity testers can be constructed using 9-volt batteries, and LED bulbs.
c. Construct rubric and discuss with students during the pre-lab.
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 9 of 17
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Dihydrogen Monoxide Environmental Issue Project
This project can be done if time allows and could be a project done near the end of the year. It
impresses on students the importance of multiple data sources and careful data analysis.
Students research DHMO and write a persuasive letter with a petition to ban DHMO. They must get at
least 10 adults to sign their petition. Only after obtaining signatures do they reveal the common name
for DHMO. This can be done by sending an “official memo” from the chemistry department explaining
that DHMO is really water, and that the students were conducting an exercise in the importance of
basing judgments on thorough data. Students love to pull this one on teachers and administrators. As
this activity gets repeated, successive groups of students will have to seek out the new teachers and other
adults to find those who do not already know about DHMO. For more on DHMO go to
http://www.dhmo.org/
Valence Graphic Organizer
Group
1
Group
2
Group
13
Group
14
Group
15
Group
16
Number
of valence
electrons
for the
atoms of
this group
Common
charge of
the ions of
this group
Common
valence
Lewis dot
structure
of the
atoms of
this group
Lewis dot
structure
of the ions
of this
group
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 10 of 17
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Group
17
Group
18
One Stop Shop For Teachers
Georgia Performance Standards Framework for Science – Chemistry
The Octet Game- Crazy Eights
This card game is meant to be used as an activating strategy to initiate instruction on bonding and
the octet rule. It is also useful to reinforce or re-teach this concept with students who need more
instruction.
To win this game, a player must “go out” by melding all cards in pairs, triplets, or quads where the
total number of electrons equals eight, or multiples of eight. Each meld total could be 8, 16 or 24.
(No meld can contain more than two elements in this game and each meld must be composed of one
red element and one blue element, but up to five cards may be used to make the meld; the more
cards the more points!)
Examples: A meld could be one Na card and one Cl card. (pair)
A meld could be two Na cards and one O card. (triplet)
A meld could be one Al card and three F cards. (quad)
Make cards representing elements of groups 1, 2, 13, 15, 16, and 17; A template is given below. To
use the template, enlarge, and cut out. Laminate if possible so that the cards will last longer. Make
one deck of cards per group of four. The cards should be printed with the red or blue lettering as
shown here in order to follow the game rules. If that is not possible, then the cards should be marked
in some way to distinguish the metals from the nonmetals. A deck needs to have 54 cards, (four sets
of the template per deck).
How to play:
The dealer deals six cards to each player. The deck is placed in the center of the table and the top
card is turned up to begin the discard pile.
The players then meld any sets of eight that they receive in their hand.
Play proceeds by the player to the right of the dealer may either pick up the discard card, or draw
from the deck. The player then discards. Play continues around the table, until one player can meld
all cards and “go out”. In going out the player may choose to discard one card, or meld all cards.
Score: 10 points for going out; 10 points for a meld that contains 2 cards;
20 points for a meld of three cards; and 20 points for a meld of four cards.
Player with the highest score at the end of a set amount of time wins, or agrees to play to a certain
number of points. (First player to score 100 points wins).
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 11 of 17
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Georgia Performance Standards Framework for Science – Chemistry
CARD TEMPLATES
Li
Na
K
Be
Mg
1e-
1e-
1e-
2e-
2e-
Ca
Sr
Ba
B
Al
2e-
2e-
2e-
3e-
3e-
N
P
O
S
5e-
5e-
6e-
6e-
F
Cl
Br
I
7e-
7e-
7e-
7e-
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 12 of 17
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Formula Models
Give students a list of compounds and a set of paper ion/atom models. The student will construct
models of the ionic and/or covalent compounds on the list. The student will write the correct
formula, if given the name, or write the correct name when given the ions or elements in the
compound. The specifics for modeling ionic compound are given below. Models for covalent
compounds can also be constructed by writing the oxidation numbers on the models.
Ion Models: Reproduce these ion models, making at least one sheet per student pair. Laminate if
possible and then have students cut them out. Make an enlarged demonstration set out
of poster board or card stock. Glue flexible magnet tape to the backs, or use magnetic sheets from
the craft store. These can be used to model the makeup of ionic compounds on a metallic backed
board or surface in the classroom.
!
1+
!
!
!
!
2+
1+
!
2+
3-
3+
!
2-
1!
!
!
1-
!
!
3-
3+
2-
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 13 of 17
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Ways to use these manipulatives:
1. Give the students names of compounds such as:
Sodium chloride (Do not give the formula.) Student pairs then check their graphic organizer, if
needed, to determine the charges of the required ions. The pair then constructs the model of the
compound, and writes the formula, based on the number of each ion used. The teacher monitors
to facilitate and check for accuracy. Continue this procedure, giving compounds that require
more thought, and more ions!
Sample list: calcium fluoride, magnesium oxide, lithium oxide, sodium bromide, strontium
chloride, aluminum sulfide, potassium nitride. At this point, two pairs may realize they must
share to demonstrate a correct model of the compound unless extra copies of the ions are
available.)
2. Place a model on the board, such as:
!
!
-1
+2
-1
Have students list the names and formulas for as many compounds as they can, that have this
same pattern of balanced charges. This task may be done as a silent round robin. Repeat,
differentiate.
Instructions for silent round robin: Groups of four have one sheet of paper, laminated card
stock, or a white board. The first student writes the formula for one compound, then passes the
list to the right. Each member in turn, adds to the list. If a member cannot think of another
answer, that member may pass after trying for at least ten seconds to come up with an answer.
If a member writes an answer that is incorrect, the next member to receive the list may go back
and correct the previous answer. This task is most effective if the “silent” aspect of the activity
is maintained. This task may also be done for warm-up, formative practice, or as a group
competition.
3. After instruction on the valence of the transition metals this activity could be repeated to
practice compounds that exhibit more than one common valence.
4. One way to differentiate instruction and assessment by using these manipulatives is to allow
students who need them to have them available during quizzes or tests.
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Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 14 of 17
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Discrepant Event with Properties of Water
Give groups of four, a re-sealable plastic sandwich bag containing two squares of glass, one plastic
pipette filled with water, and five toothpicks.
Step one: Students make a small puddle of water on the counter top. (Alternatively, see how many
drops of water can be placed on a penny before the water spills over the edges.) Observe this
convex surface. Why does the meniscus in a graduated cylinder filled with water have a concave
shape?
Step two: Place two drops of water on one of the pieces of glass. Place the second piece of glass on
top of these drops and press the pieces of glass together like a sandwich. Attempt to separate the
two pieces of glass by pulling directly up and down on the two pieces. Why is this so hard to do?
Step three:
ƒ
ƒ
ƒ
ƒ
ƒ
Bend 5 wooden toothpicks in half so that each toothpick forms a “V” but does not break
apart.
Place the bent toothpicks on the center of a dry, smooth surface, arranging them so that the
points of the Vs make a small circle in the middle. It will look like a flower.
Drop two or three drops of water into the center of this circle without disturbing the
toothpicks.
Record your observations.
What happened to the toothpicks? Why?
Write an essay explaining how the unique properties and molecular structure of water caused the
phenomena just observed.
Teacher note: These demonstrations are very simple, but are favorites with the students.
Brief explanations:
Step one- surface tension results from cohesion and adhesion due to the hydrogen bonds between
the polar covalent water molecules.
Step two- cohesion and adhesion due to the hydrogen bonds between the polar covalent water
molecules holds the glass together.
Step three- capillarity of the water into the spaces in the toothpick (which is made of hollow plant
cells) as a result of the hydrogen bonds between the polar covalent water molecules.
PAT Formula Bee
Conduct this activity in the format of a spelling bee. The contestants stand, until they miss one.
This can be used as a warm-up before a quiz. A variation: groups write the formula of a white
board and all groups that get the formula correct score a point.
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 15 of 17
Copyright 2006 © All Rights Reserved
One Stop Shop For Teachers
Georgia Performance Standards Framework for Science – Chemistry
Analysis of Reactions Performance Task for Summative Assessment: Students outline all the
physical and chemical changes that occurred in the bag reaction and relate the changes to
solutions, energy change, gas pressure, and equilibrium. Balanced equations should be written
for the reactions that occurred and the type of reaction should be identified.
Concept Map Performance Task: Reaction Types
Design a concept map that diagrams the five types of chemical reactions studied in this unit.
Show how elements and compounds are changed through these reactions.
Show connections and relationships between the kinds of reactions, the type of reactants
(elements, ionic and covalent compounds) and products (elements, ionic and covalent
compounds). It is not necessary to show actual equations in this map.
A student could use the generic equations below as a starting place for the concept map, using a
key for letters. A sample completed concept map follows. Students should be allowed some
flexibility in the design, and the product could be produced using appropriate software, or it
could be done using a traditional format.
Although one goal of the concept map is for it to be so clear that no further explanation is needed,
the student should be able to discuss the reasoning behind the design of the map.
Generic Reaction Formats:
Composition (synthesis):
Decomposition:
Double Replacement (Ionic reactions):
Single Replacement (Displacement):
A +X
AX
AX
A+X
AX + BY
AY + BX
AX + B
BX + A; AX +Y
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 16 of 17
Copyright 2006 © All Rights Reserved
AY +X
One Stop Shop For Teachers
Georgia Performance Standards Framework for Science – Chemistry
SAMPLE CONCEPT MAP OF TYPES OF REACTIONS
Elements
Decomposition
Composition
Single
replacement
Compounds
Ionic Compounds
replace
ment
New ionic
compound
Ionic
compound 1
Covalent Compounds
Organic
compounds
Oxygen
Combustion
(rapid oxidation)
Carbon dioxide
Ionic
compound 2
Double
Replacement
Ionic
Compound 3
Molecular
compound
Water
Georgia Department of Education
Kathy Cox, State Superintendent of Schools
Chemistry y Exploring Change – Bonds, Energy and Reactions
October 2006 y Page 17 of 17
Copyright 2006 © All Rights Reserved
Compound 4
or
Precipitate