Course Profile Science, Grade 9 academic, Public

Unit 3

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Any references in this document to particular commercial resources, learning materials, equipment, or technology reflect only the opinions of the writers of this sample Course Profile, and do not reflect any official endorsement by the Ministry of Education or by the Partnership of school Boards that supported the production of the document.

Acknowledgments

Public District School Board Writing Teams – Science

Course Profile Writing Team

Arthur Prudham, Lead Writer, Waterloo Region District School Board and

Science Co-ordinators and Consultants Association of Ontario

Tom Card, Peel District School Board

Bob Callcott, York Region District School Board

Chuck Hammill, Peel District School Board

Heather Troup, Peel District School Board

Peter Tse, York Region District School Board

Contributing Writers (Unit 5)

George Huff, Fiona White, Allan Smith

Internal Reviewers

Dave Arthur, Ontario Society for Environmental Education (OSEE); Paulette Luft, Philip Marsh, Elaine Sturm, Peel DSB; Fiona White, Kawartha Pine Ridge DSB and STAO

Lead Board

Peel District School Board

Allan Smith, Project Manager

Partner Boards

Kawartha Pine Ridge District School Board, Ottawa Carleton District School Board, Waterloo

Region District School Board, York Region District School Board

Associations

Ontario Society for Environmental Education (OSEE)

Science Co-ordinators and Consultants Association of Ontario (SCCAO)

Science Teachers Association of Ontario (STAO)

Unit 3: Chemistry: Atoms and Elements

Time: 22 hours

Unit Description

Students design and conduct investigations into the properties of elements and compounds with a focus on laboratory safety. The topics of the unit lend themselves naturally to experimentation and provide opportunities for students to collect, record, organize and interpret data. The Particle Theory and atomic theories are used to explain observations. The extraction and recycling of elements in Canada and the impact of related technologies on the environment are topics of a research investigation.

Strand(s) and Expectations

Strand(s): Chemistry

Overall Expectations: CHV.01, CHV.02, CHV.03.

Specific Expectations: CH1.01 to .15; CH2.01 to .10; CH3.01 to .04.

Activity Titles (Time and Sequence)

Activity 1	What is Chemistry?	150 minutes
Activity 2	Inquiry	90 minutes
Activity 3	Using Theories	180 minutes
Activity 4	Elements, Ions, and the Periodic Table	240 minutes
Activity 5	Elements and Compounds	210 minutes
Activity 6	Extraction of Elements	240 minutes
Activity 7	End-of-Unit Task	210 minutes

Prior Learning Required

Students should have some background knowledge of properties and changes in matter from Grade 5 and pure substances and mixtures from Grade 7. Until full implementation of the Grade 1-8 program the amount of guidance, review, and new teaching required in the activities will change from year to year. Students are familiar with some parts of the Particle Theory, changes of state, energy transformations, safe use of some apparatus and equipment, making observations, identifying variables, and designing and conducting controlled experiments or fair tests.

Unit Planning Notes

Required planning is described for each of the activities. Some activities require specific chemicals and solutions. These should be acquired and/or prepared ahead of time with reference to the Workplace Hazardous Materials Information System (WHMIS). Alternate demonstrations or experiments may be used if suggested reactants are not readily available or cannot be purchased (See resource section for suggested sources of demonstrations.).

Attention to safe laboratory practices, the use of small quantities of chemicals wherever possible (both for economic and environmental reasons) and proper disposal of chemicals are extremely important and must be modelled by the teacher at all times. Unfamiliar reactions must be tried prior to use in the classroom.

It may be necessary to book a guest speaker, or video, to provide information about extraction of elements and related careers in Activity 6. Research time for Activity 6 is also required and should be booked in advance with the library/resource teacher or research materials made available in the classroom.

The end-of-unit task is used for summative assessment and evaluation and consists of two parts. The experimental design portion is introduced in Activity 2, with the experiment being performed in Activity 7. The observation period (monitoring the rusting of iron) extends over several days and might not be completed prior to the start of the next unit. As an alternate approach, a teacher may wish to start the experimental part of Activity 7 before Activity 6. This would allow completion of all assessment and evaluation items before the next unit is started.

Throughout the unit students record notes in their notebook and use their Science Journal to record reflections about their own learning, their goals for the course, and their ability to work individually and with others.

A Note on Science Fairs

This unit provides opportunities for students to begin open-ended, experimental inquiry. When they have access to a science fair, students should be encouraged to present their findings there for a variety of reasons: preparation for a science fair requires self-assessment based on clearly-stated criteria; presenting to an alternative audience deepens understanding of the topic; judges are able to provide expert feedback on both process and product; and wider recognition of good work may motivate students to pursue further inquiry.

Teaching/Learning Strategies or Activities

Activity	Strategy	Description
1	Teacher demonstration; student experimentation	After the teacher demonstrates the safe use of laboratory equipment, physical and chemical properties, and the evidence for chemical and physical changes, students independently apply their learning to an investigation.
2	Inquiry - experimenting	Students are introduced to the end-of-unit task and develop required skills by designing, conducting, and recording results of a controlled experiment.
3	Brainstorming; video presentation; note making; teacher-led discussion; hands-on activity	Students consolidate their knowledge of, and clarify any, misconceptions regarding the Particle Theory, atomic theories and the nature of sub-atomic particles. They perform flame tests for known and unknown compounds and relate the colour produced to the change in position of electrons.
4	Hands-on activity; problem solving; collaborative small group work; Socratic lesson	After examining and grouping samples of metallic and non-metallic elements, students compare their classification with the Periodic Table. They relate their knowledge of atoms and sub-atomic particles to the atomic structure of various elements using Bohr-Rutherford diagrams.
5	Teacher demonstration or student experiment; inquiry - experimenting; model building	Through observations of electrolysis of water, students develop an understanding that compounds are composed of elements in whole number ratios. By comparing the reactions of water and hydrogen peroxide, students recognize that slightly different ratios result in distinctly different properties. They extend their knowledge of ratios in developing simple chemical formulae and constructing molecular models.
6	Inquiry - researching and communicating	The extraction and recycling of elements in Canada, and the impact of related technologies, are introduced. Student pairs conduct further related research on a selected element and report findings to their peers.
7	End-of-unit task: Inquiry- experimenting; laboratory practical	This is a summative assessment to evaluate students’ knowledge of atoms and elements, safety procedures and experimentation skills. This is accomplished through individual investigations and a practical laboratory test.

Assessment/Evaluation

Activity	Assessing and Evaluation	Method or Instrument
1	Knowledge of safety procedures	Quiz
2	Safe laboratory practice; data organization and written communication skills	Observational checklist; rubric (diagnostic)
3	Laboratory technique; understanding concepts	Observational checklist; student self-assessment; peer-assessment; quiz
4	Understanding of concepts; problem solving	Notebooks and handouts; graphic organizer
5	Experimental design; organization of data; model-building	Rubric; peer- or self-assessment
6	Research skills; presentation skills	Rubrics; peer evaluation
7	Design, performance, and report of experiment; practical tasks from all previous activities	Rubric; checklist; marking scheme

Resources

Chem 13 news. Department of Chemistry, University of Waterloo.

Crucible. Science Teachers Association of Ontario

Jones, G., M. Jones, and D. Acaster. Cambridge Coordinated Science: Chemistry. Cambridge: Cambridge University Press, 1993.

Outlines real-life applications of elements and chemical reactions. Includes chemistry of the Earth and the solar system.

Liem, T.K. Invitations to Science Inquiry. 2nd edition. Paperback. Chino Hills: Science Inquiry Enterprises, 1990. Includes demonstrations for chemistry, physics, biology, and Earth Science.

ISBN 187810 621 X

Selinger, B. Chemistry in the Marketplace. Fourth Edition. Toronto: Harcourt Brace Jovanovich Group, 1989.

An overview of chemistry of everyday products; a useful resource for teachers, but written at a senior level.

Summerlin, L.R., C.L. Borgford, and J.B. Ealy. Chemical Demonstrations. A Sourcebook for Teachers. Volumes 1 and 2. Washington: American Chemical Society, 1988.

An excellent source for demonstrations; includes brief explanations regarding the chemical reactions involved. Available from: American Chemical Society, Distribution Office, Department 225, 1155 16th Street NW, Washington, DC 20036 1-800-227-5558.

Web Site

http://www.stao.org/safety.htm

Activity 1: What is Chemistry?

Time 150 minutes

Description

In this activity, students are introduced to chemistry and some key terms used in discussing chemical and physical change through observations of intriguing reactions. The teacher demonstrates some reactions and, after acquiring full knowledge of safe laboratory procedures, students perform their own experiments. The emphases are on making and recording observations, and using the observations to differentiate between physical and chemical change.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH1.14, CH2.01, CH2.02, CH2.08.

Planning Notes

The materials for the teacher demonstrations and student activities must be prepared in advance. The teacher ensures that the demonstrations in Strategy 1.2 illustrate a variety of evidence of chemical change (refer to the list in Expectation CH1.14) and the five postulates of the Particle Theory. See the Resources for sources of chemistry demonstrations. A trial run of unfamiliar demonstrations is strongly advised.

Some changes - often physical changes - can be explained by the Particle Theory, but others cannot - generally chemical changes. In Activity 3, students are lead to see that new theories are needed to explain some of the changes they have observed and they are introduced to a progression of atomic theories which have greater explanatory and predictive capacity than does the Particle Theory.

The teacher should model proper handling and disposal of chemicals. Students must be shown how to access a Material Safety Data Sheet (MSD Sheet) for each chemical used in class. A summary sheet of safe laboratory procedures should be given to each student if this was not done at the start of the year.

The teacher carefully demonstrates the use of the Bunsen burner prior to first student use. Safety in the laboratory may also be addressed through a video. The students should demonstrate their understanding of safety rules before proceeding to Strategy 1.2.

There is an ongoing discussion as to whether dissolving is a physical or chemical change. For the purpose of this profile, dissolving is considered a physical change. Large quantities of heat are released in some dissolving reactions (e.g., sulfuric acid in water); questions pertaining to such reactions may be appropriate for the Wonder Wall.

Prior Learning Required

Students should have the ability to make accurate observations and to describe physical and chemical properties of matter.

Teaching/Learning Strategies

1.1 Student Activity: The students observe intriguing activities and record observations in their Science Notebooks. Terms are defined and recorded. Safety procedures are discussed, and a summary safety sheet is read and stored in the Notebook for future reference. MSD Sheets for several chemicals are examined.

Teacher Facilitation: Perform the demonstrations and draw attention to appropriate vocabulary such as reactants, products, and chemical and physical properties. Highlight evidence for chemical and physical change. Encourage questions that may be appropriate for the Wonder Wall.

Some demonstrations may include: ammonium nitrate in water (endothermic reaction); solution of potassium iodide mixed with a solution of lead (II) nitrate (precipitate and colour change); burning paper (odour); burning magnesium (emission of light and a new product); electrolysis of water (gases formed); cutting up paper (physical); and boiling water (physical).

It is not necessary that the students understand the details of the chemical reactions. Rather, evidence of chemical and physical change and accurate observations are emphasized. While performing the demonstrations, safe laboratory procedures are modelled, and disposal of chemicals is discussed.

Students should be aware of the value of using small quantities of chemicals, both from an economic and environmental standpoint. A summary sheet of safe laboratory practices is reviewed with all students. Workplace Hazardous Material Information System (WHMIS) and rights and responsibilities of individuals in the workplace are discussed with the students. MSD Sheets using a specific chemical (e.g., Mg or Pb(NO₃)₂) are discussed with students in conjunction with the demonstration.

1.2 Student Activity: The students complete a series of activities to independently determine the evidence for and differentiate between physical and/or chemical change. They record observations in their Notebooks and justify their ideas using observations from the activities. The routine use of protective eyewear in all student laboratory work is emphasized in this activity.

Teacher facilitation: Set up a series of activities where the mixing of reactants results in changes indicating chemical and/or physical change. Some possible activities include: heating of a bimetallic strip (physical); mixing of 5.0 mL of alcohol with 5.0 mL of water (physical); heating of the ball and ring apparatus (physical); igniting a wooden splint (chemical); diffusion of potassium permanganate in hot and cold water (physical); pushing of a droplet of water and a droplet of alcohol on wax paper (physical); air thermometer/palm glass (physical); baking soda in water (physical); Alka-Seltzer tablet in water (chemical); baking soda in acid (chemical); bleach in ketchup (chemical); magnesium in dilute hydrochloric acid (chemical); crushing sugar cubes (physical); melting ice (physical); crystallizing supersaturated sodium acetate solution (physical); Benedict’s test for sugar (chemical); and iodine test for starch (chemical).

Assessment/Evaluation Techniques

A quiz to ensure student understanding of safe laboratory practices should be given prior to Strategy 1.2. Several scenarios (visual, written, or teacher dramatization) depicting hazardous laboratory situations are presented to the students. The students then identify the incorrect procedure and describe remediations.

Accommodations

· It is possible that some students are allergic to common chemicals. Be aware and involve them in discussing the ideas without coming in contact with the chemicals.

Resources

Liem, T.K. Invitations to Science Inquiry. (see main resource list).

Summerlin, L.R., C.L. Borgford, and J.B. Ealy. Chemical Demonstrations. A Sourcebook for Teachers. Volumes 1 and 2. Washington: American Chemical Society, 1988.

Video

Laboratory Safety: A Practice For Life. Available from STAO.

Activity 2: Inquiry

Time 90 minutes

Description

A detailed look at a chemical reaction identifies the importance of variables in chemical investigations. The blue bottle activity is observed and students identify variables that may affect the length of time for a colour change to occur. Students then design and carry out a controlled experiment using the blue bottle reaction. The challenge is to change a chosen variable so that the colour change (from blue to colourless) occurs in a specified time. The experimental design portion of the end-of-unit task is outlined.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH2.01, CH2.03, CH2.05, CH2.06, CH2.07.

Planning Notes

Students need graduated cylinders and balances in addition to the materials for the blue bottle solution (see Attachment). A handout that outlines the general requirements for a science report can be kept in the students’ notebook for this experiment and for future reports. Limit the time spent on the experiment to one period. The students do not need to understand the chemical reaction, but should demonstrate understanding of cause-and-effect relationships.

Prior Learning Required

Students have prior knowledge of safety practices and procedures. Students also require some background in experimental design and the control of variables.

Teaching/Learning Strategies

2.1 Student Activity: Students are introduced through a handout to the end-of-unit task, Activity 7.1. They are encouraged to begin the background research on rusting of iron.

Teacher Facilitation: Provide a handout describing Activity 7.1 and discuss the activity as well as the assessment and evaluation. Suggested timelines for this research should be given to students. Emphasize the need for careful manipulation of variables and accurate observations. The following activity allows students to practise these skills.

2.2 Student Activity: The students observe the blue bottle demonstration, and together, as a class, devise a graphic organizer that identifies possible variables that affect the time of the reaction (i.e., how long it takes for the blue colour to change back to clear). The students participate in the discussion of the experimentation process and record design ideas in their notebooks. A teacher-led discussion of the assessment criteria and the evaluation of the laboratory follows. Then, in groups, students work with an assigned/chosen variable (selected from the organizer) and design the experimental method, data tables, etc. The challenge is to change the variable in order to obtain a specific reaction time determined by the teacher. Students are introduced to the end-of-unit task that involves the designing and performing of an experiment to determine which of two variables has the greater effect on the rusting of iron.

Teacher Facilitation: Demonstrate the blue bottle reaction, pointing out evidence of chemical change. (See Attachment for Blue Bottle Reaction.)

The students do not need to understand the chemical reaction, but should demonstrate understanding of cause-and-effect relationships. As some students may choose a variable that has no effect on the reaction time, the teacher should emphasize that such results have value.

The variables students might suggest include quantity of glucose, quantity of potassium hydroxide, quantity of water, quantity of methylene blue, amount of shaking, and quantity of air.

Help the class develop a graphic organizer of variables, and conduct a review of scientific method - hypothesis, purpose, method, number of trials, data collection, analysis and meaning of data, communication of results, etc. A handout of the format for science reports may be appropriate.

Note: In order to maintain the usefulness of this activity it is important that students not be given the explanation.

Assessment/Evaluation Techniques

The experiment report could be assessed using a rubric based on TSM - Partial Rubric for Inquiry Experimenting, page xi in Phase 1.

Students’ ability to follow safe laboratory practices can be observed and assessed using a checklist.

Accommodations

· Students with impaired motor skills may make observations, predictions, and suggest modifications while a partner performs the physical activity.

Resources

Liem, T.K. Invitation to Science Inquiry, as well as other chemistry resources for the Blue Bottle Reaction.

Attachment: The Blue Bottle Experiment

Teacher Demonstration:

Materials: 500 mL Erlenmeyer flask, stopper, 5 g of potassium hydroxide (KOH), 3 g of glucose or dextrose, methylene blue

Procedure: Dissolve the potassium hydroxide (KOH) and glucose in about 250 mL of water. Add four drops of methylene blue and stopper the flask. This colourless solution turns blue when the flask is shaken. As the solution sits, it returns to colourless. Explanation: The methylene blue is reduced to a colourless compound by the alkaline sugar solution. When the stoppered flask is shaken, the colourless solution is re-oxidized by the oxygen above the liquid and the blue colour of methylene blue appears. This reaction may be repeated many times during the class period. After a few hours, the flask may need to be unstoppered to replenish the supply of oxygen.

Student Experiment:

One recipe for the blue bottle reaction is the following:

For a 125 mL flask, dissolve 1.2 g potassium hydroxide (KOH), 0.8 g glucose and one drop of methylene blue in 75 mL water. Stopper.

Students vary the composition as part of their experimental procedure.

Note: Potassium hydroxide pellets should not be handled by students (SAFETY). The chemical is very corrosive not only to skin but also to glassware, particularly in pellet form. The teacher could prepare some solutions of potassium hydroxide for use in the experiment and store them in plastic containers. In the short term glass containers would also be satisfactory, but the message that strong bases damage glass can be a lesson here. The solution described above, and ones 10% to 15% more concentrated and less concentrated may give reasonable rate variations. Try them in advance of class to confirm.

Activity 3: Using Theories to Explain Observations

Time: 180 minutes

Description

Observations from Activity 1 are matched with Particle Theory postulates. Not all reactions are readily explained by this theory; this leads to an examination of atomic theories. Students view a video, or use print material to record main ideas as described by Dalton, Thomson, Rutherford and Bohr. The Bohr Model of the atom is explored by performing flame tests.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH1.02, CH1.06, CH2.10, CH3.03.

Planning Notes

Obtain a selection of videos or collection of print material outlining the history of development of the Atomic Theory. Prepare a worksheet that allows students to summarize atomic theories and key vocabulary. Discharge tubes and spectroscopes may be good supplements. Prepare solutions and wood splints or nichrome loops for flame tests (see Teacher Facilitation). These solutions and splints may be kept for use from year to year.

Prior Learning Required

· Some aspects of the Particle Theory were introduced in Grade 7, but it is unlikely that all postulates would have been discussed thoroughly.

· The characteristics and utility of scientific models (expectation CH1.01) were presented in Unit 1, Activity 5.

Teaching/Learning Strategies

3.1 Student Activity: With teacher assistance, students recall postulates of the Particle Theory. They generate a two-column chart with the headings Postulate, Evidence.

Teacher Facilitation: Record students’ recollections of the Particle Theory on chart paper or blackboard. Formalize the five postulates of the Particle Theory and record them on the left-column of the two-column chart. Help students use observations from Activities 1.1 and 1.2 to provide evidence for one or two of the postulates and have them record this in the right-column. Direct the students to complete the chart for the remaining postulates. Extend the discussion to those reactions that were not easily explained by the postulates of the Particle Theory. This requires a more thorough understanding of the nature of particles which is provided by successive atomic theories, introduced in the next activity

3.2 Student Activity: Students watch a video outlining the development of atomic theories. Alternatively, print material is read. Students summarize main ideas in their notebook, using a four-column chart to organize name of scientists and description of their theory, evidence to support the theory, strengths of the theory, and weaknesses of the theory.

Teacher Facilitation: Select a video and/or suggest additional references (e.g., print material, Internet sites) to supplement the textbook. As models of the atom are discussed, use them to explain some properties that the Particle Theory doesn’t explain (e.g., Thomson’s model explains electrostatic attraction). In activities to come, the teacher uses atomic theories to explain flame tests and chemical bonding. It is important that students realize that models evolve as more sophisticated observations are made.

3.3 Student Activity: Students participate in a discussion of the characteristics of protons, electrons and neutrons, atomic number, and mass number. Given the atomic and mass numbers of five substances, students calculate the number of protons, electrons, and neutrons in each. As an application of subatomic particles, students complete a homework reading assignment on radioactive isotopes.

Teacher Facilitation: Lead a discussion of the subatomic particles. After the characteristics (relative mass, charge, and location) of the subatomic particles have been discussed, introduce the concept of atomic number and mass number. Then present a representative diagram of the Bohr-Rutherford model, such as sodium (atomic number 11, mass number 23 = 11 protons and 11 electrons, 12 neutrons). The diagram includes electrons at three different energy levels. Provide at least five more examples (e.g., Be, F, Cl, I, Ag) for students to work through so that they may consolidate the relationship between atomic and mass numbers.

Radioactive isotopes, their uses and related technologies are briefly introduced at this time (e.g., the use of carbon-14 for dating fossils, cobalt-60 for radiation therapy, deuterium in heavy water, uranium-235 in CANDU reactors). Students are encouraged to add questions to the Wonder Wall for use in the culminating activity for the course.

3.4 Student Activity: Students perform flame tests and record the colour of the flame produced by burning each compound. Once they have completed ten known samples and linked flame colour to the presence of specific cations, they repeat the flame tests with three unknowns A, B, and C, and determine the identity of the cations in the unknowns.

Teacher Facilitation: Review the safe use of Bunsen burners. Prior to students performing the flame test, explain how the input of energy (heat in this case) raises electrons to a higher energy level and the return of the electron to a lower level is accompanied by the release of energy in the form of light. The quantity of energy released, and therefore the colour of light in the flame, is characteristic of the substance. Set up a series of flame test-solutions. The following are suggested: two potassium compounds, two sodium compounds, two copper compounds, one each of calcium, lithium, strontium, and barium compounds. Three of the solutions are set up as unknowns A, B, and C. Solutions are stored in small juice bottles where wooden splints are soaked in each of the solutions prior to burning. Caution the students not to burn the splints, only the solution (about five seconds) so they can be reused. Periodically replenish the solutions and splints.

NOTES:

1. The flame colour of sodium is so intense that it may shield other results, not only at a particular laboratory station, but often throughout the room. Suggest that students do all other tests first, and that no group perform the sodium test until all others are done.

2. Care must be taken that solutions are not contaminated by splints being transferred from one solution to another during the activity.

Assessment/Evaluation Techniques

Observation of laboratory technique and ability to follow laboratory procedures can be assessed using a checklist. Student self-assessment of correct information in the chart of Particle Theory postulates can be performed by comparing with teacher-prepared chart. Peer-assessment of the Atomic Theory chart could be performed using a checklist. A quiz to check for understanding of concepts in both the Particle Theory and atomic theories may be useful.

Accommodations

Students who have difficulty perceiving colours may need to work with a partner in completing the flame tests.

Resources

Video

Northey Productions. Electron Arrangement and Bonding: Introducing the Players, The Rutherford-Bohr Model.

TVO videos: Structure of the Atom Series

Smaller Than the Smallest

The Rutherford Model

The Bohr Model

Activity 4: Elements, Ions, and the Periodic Table

Time: 240 minutes

Description

Students review and extend their knowledge of atoms and elements to include ions. Students examine samples of metallic and non-metallic elements and group them into families based on observed properties. They compare their classification with that of the Periodic Table. The Periodic Table is further examined using Bohr-Rutherford diagrams.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH1.03, CH1.05, CH1.07, CH1.08, CH1.09, CH1.10, CH1.11, CH1.13, CH2.01, CH2.07, CH2.08, CH2.10.

Planning Notes

Materials required: samples of metallic and non-metallic elements; conductivity apparatus; teacher-prepared grid/chart of elements in groups; density problem worksheet or text assignment; teacher prepared worksheet on ion formation; video featuring properties of family of elements (optional).

Prior Learning Required

Students have learned about models in general, the simplified Bohr-Rutherford model, and density in Unit 1. For many students, this is their first exposure to the Periodic Table and some time likely has to be spent on its use as a classification tool. However, the emphasis of this activity is on the properties of families within the table and students should not become overly concerned with all the details within it.

Teaching/Learning Strategies

4.1 Student Activity: The students relate their knowledge of atomic theories gained in Activity 3 to a discussion of the characteristics of atoms and elements. They make records in their notebooks to emphasize that elements contain only one type of atom, that atoms of one element are similar to one another, and that atoms of different elements are unique to that element. The students then observe a number of metallic and non-metallic elements and record physical properties such as: state at room temperature; melting and boiling points (from data tables, not experiments); conductivity; malleability and ductility; lustre and colour; density. Students group the elements into families based on criteria developed from all their observations and share their classification with the class. They then compare their classification with that of the Periodic Table and, with teacher facilitation, discuss similarities and differences. Students observe a teacher demonstration illustrating reactivity of alkali metals. Students then make predictions about the properties of elements grouped in different families. Students complete a series of density problems for homework.

Teacher Facilitation: After leading a discussion of the general characteristics of elements while students make notes, show the class a variety of metallic and non-metallic elements, and review the meaning of the characteristics described above. Then show the students how to perform the tests required in the student activity and direct them in making a chart in which to record observations.

Once observations are made, guide the students in comparing their classification with that suggested by the Periodic Table. A demonstration that shows the reactivity of alkali metals is then performed. It may be useful to use a video to help illustrate how families of elements are grouped in the Periodic Table. Groupings based on both physical and chemical properties are emphasized. Following the demonstration and/or video, assign three unfamiliar elements from the same family (e.g., magnesium, calcium, strontium) and have the students order them according to a specified chemical and physical property. Provide a set of density problems, either on a worksheet or from a text, which students perform at home. (Expectation CH1.13). Remind students of the work done in Unit 1, Weird Water on density.

4.2 Student Activity: The students complete a teacher-prepared grid/chart with Bohr-Rutherford diagrams for the first twenty elements. Based on the distribution of the electrons, students working in groups deduce the reason the elements are placed as they are in the chart.

Teacher Facilitation: Prepare a blank chart of the Periodic Table (see Appendix). Through guided discussion, lead the students to understand the rules for drawing Bohr-Rutherford diagrams. Once the students have filled in their periodic tables, ensure that students understand that members of a family (vertical column) share the same number of electrons in the outermost energy level and that members of a period (horizontal row) share the same number of energy levels. The alkali metal, halogen and noble gas families are emphasized.

4.3 Student Activity: Students review the stable nature of the noble gases and predict, from the Bohr-Rutherford diagrams, the reason for this stability. Students are shown that ions are formed by the gain or loss of electrons and then complete a worksheet illustrating the formation of common ions.

Teacher Facilitation: Conduct a Socratic lesson (a series of directed questions) that highlights: the number of electrons in the outer energy level required for stability (eight electrons or two in the case of helium); the likelihood of gaining electrons (non-metals) or losing electrons (metals) for atoms to become stable; and the resulting charges on the ions. Questions relating to ionic bonding could be posted on the Wonder Wall or, as an extension, ionic bonding could be taught as a separate lesson.

Assessment /Evaluation Techniques

Notebook entries and a quiz can be used to assess accuracy of basic concepts. The quiz (an in-class or take-home assessment) could take the form of a graphic organizer upon which students indicate learned trends of the Periodic Table

The accuracy of Bohr-Rutherford diagrams, and the placement of elements, can be assessed using the handouts.

Accommodations

Please refer to TSM.

Resources

www.liv.ac.uk/Chemistry/links/refperiodic.html

www.uky.edu~holler/periodic/periodic.html

Video

Atoms and Their Electrons. Available from Classroom Video

Attachment: Blank Grid for Bohr-Rutherford Diagrams

1 Hydrogen							2

3	4	5	6	7	8	9	10

11	12	13	14	15	16	17	18

19	20	Instructions: Draw the Bohr-Rutherford diagrams for the atoms of each of the first 20 elements. Hydrogen has been done for you in box #1. Helium will be drawn in box #2, etc.

Activity 5: Elements and Compounds

Time: 210 minutes

Description

Students understand that the smallest particle of a compound is a molecule and that molecules are composed of atoms. Following a brief review of the evolution of atomic theories and the nature of elements, students relate Dalton’s ratio of whole numbers to the formation of molecules. Students then construct models of some of the more familiar molecules and ions.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH1.04, CH1.05, CH1.12, CH1.15, CH 2.03, CH2.05, CH2.09.

Planning Notes

Materials required:

· Hoffman apparatus for the electrolysis of water (either as teacher demonstration or for groups of students to perform)

· molecular model kits and other materials with which to build models (e.g., modelling clay, toothpicks, straws, foam balls)

· 3% hydrogen peroxide (purchased at any pharmacy, stored in the refrigerator)

Prior Learning Required

Students have used Bunsen burners in previous activities but will require reminders of safe use.

Teaching/Learning Strategies

5.1 Student Activity: Students observe or refer to an earlier demonstration of the electrolysis of water and record the volume and identity of gases produced. Through a guided discussion, they are led to understand that molecules are combinations of atoms. They learn that in water there are twice as many hydrogen atoms as oxygen, and that atoms always combine in whole number ratios when forming molecules (Dalton’s ratio). Students complete a short note on this concept.

Teacher Facilitation: Using the electrolysis of water as a demonstration, introduce the concept of combination of atoms in whole number ratios to make compounds. Once the gases have been collected, demonstrate the test for oxygen gas (glowing splint) and hydrogen gas (burning splint). The teacher may choose to have students perform the electrolysis laboratory activity. If the students perform the activity, a Hoffman apparatus should still be set up to collect samples of gases for testing. The students should only collect small volumes of gases, especially hydrogen gas because of its explosive nature. Ensure that students carefully record the volume ratio, the test results, and the identity of the gases.

5.2 Student Activity: Students compare the reaction of manganese dioxide with water and with 3% hydrogen peroxide. They determine potential variables and design and perform a controlled experiment. Students design their own chart for recording data which includes qualitative and quantitative observations from before and after the reactions. Students determine the identity of any gas produced using the splint tests from Activity 5.1. Students predict the identity of any other product.

Teacher Facilitation: Introduce the activity by providing the formula of hydrogen peroxide (H₂O₂) from the label, MSDS sheet, name, etc. and compare it to the formula of water.

Review the student designs before experiments are performed. Following the experiment, emphasize how two compounds with very similar formulae have different properties. Extensions can include discussion of students’ predictions, a consideration of the storage of hydrogen peroxide in the home, the role of catalysts, and the comparison of carbon monoxide and carbon dioxide. Students are encouraged to add questions to the Wonder Wall.

5.3 Student Activity: The students brainstorm examples of simple compounds and their formulae. From the examples, the students predict the structure of, and build, five molecules using modelling clay, toothpicks, or other suitable material. Students then construct models of the same molecules using model kits and compare the currently accepted model with their predicted one. They describe their comparisons in their Notebooks.

Teacher Facilitation: Record on the blackboard or chart paper the compounds and formulae suggested by the students (e.g., H₂O, H₂O₂, CO₂, CO, NH₃, CH₄, O₂, H₂, CH₃OH). As students make their predictions of the structure of the molecules, monitor the class and offer assistance and encouragement as needed. Then provide model kits, review the parameters of construction (e.g., all holes must be filled), and have students construct models of the compounds, comparing them to their predictions. Students are encouraged to add questions to the Wonder Wall. A possible extension is the nature of covalent bonding.

Assessment /Evaluation Techniques

Experimental design and organization of collected data are assessed and evaluated. Models are peer or self-assessed for accuracy. Molecular recognition and model construction is evaluated during the practical test in Activity 7.

Accommodations

· All students should take part in discussions and laboratory activities. Alternate timelines may be necessary for some students.

· Students with impaired fine motor control can make and record observations while their partner performs the laboratory activity.

Activity 6: Extraction of Elements

Time: 240 minutes

Description

The extraction and recycling of elements in Canada, and the impact of related technologies on the environment, are introduced in the Activity 6.1. Student pairs select an individual element and outline environmental and economic considerations associated with extraction of that element.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH2.04, CH3.01, CH3.02, CH3.04.

Planning Notes

Teachers might wish to explore the availability of a guest speaker who could talk to students from first-hand experience about the benefits and costs of extracting specific elements and about related careers. If a guest speaker is unavailable, then consider video or text material. Pre-arrange research time and resources with the teacher/librarian. In addition, teachers may wish to begin keeping their own periodical file of news reports and magazine articles dealing with the use of elements and their extraction. Every effort should be made to select Canadian examples such as aluminum, iron, silver, copper, mercury, and nickel.

Prior Learning Required

Research skills, including bias detection, have been developed in earlier units and are required in this activity. Students might benefit from a review of note-taking and questioning techniques to use with guest speakers.

Teaching/Learning Strategies

6.1 Student Activity: The students observe a presentation on the extraction of elements in Canada. They discuss related careers. Notes and questions are recorded in the notebooks.

Teacher Facilitation: Arrange for a guest speaker, select a video, and/or present information in text form about the extraction of elements in Canada, including economic and environmental considerations. Possible guest speakers may come from businesses such as Alcan, Dofasco, Falconbridge, Inco, and Stelco. The technologies involved in the extraction and recycling of substances, and the impact of these processes on the environment, are presented.

6.2 Student Activity: Each student pair selects an element and researches information about its chemical and physical properties, use and importance, impact on the environment, technologies necessary for its detection, extraction, recycling, or reclamation (e.g., from spills or leaching into soil, waterways, or ground water), hazards to the human body, etc. Post-consumer reclamation may be considered. The information obtained is to be presented in an interesting format (e.g., poster, pamphlet, video, web site, presentation).

Teacher Facilitation: Ensure that each student pair selects a different element. Remind students to be aware of embedded biases in literature, web pages, and press coverage. Organize the presentations so that one member of each pair stays with the display to explain it to other students. The other member moves from station to station at designated intervals, recording information about each project, and evaluating the display. The roles of the partners are then reversed.

Assessment /Evaluation Techniques

Peer evaluation of student presentations can be used in conjunction with teacher evaluation. The teacher could develop a checklist of qualifiers with students using the Partial Rubric for Inquiry - Researching (TSM p. xii - Phase 1).

Accommodations

· All students should take part in preliminary discussions, research and presentations. Alternate timelines and presentation methods may be necessary for some students.

Resources

News and magazine articles about the benefits, costs, and impact of extracting elements in Canada.

TSM Bias Assessment of an Article (page ii – Phase 1).

Activity 7: End-of-Unit Task

Time: 210 minutes

Description

In this final activity students apply their skills of experimental inquiry and manipulation of variables, and their knowledge of elements and compounds, to an analysis of the effect of variables on the rusting of iron. Emphasis is on design and the experimentation process. Students should consider at least two variables in their design. They also demonstrate the knowledge and skills gained in this unit through a summative, practical test.

Strand(s) and Expectations

Strand(s): Chemistry

Expectations: CH2.01, CH2.03, CH2.05, CH2.06, CH2.07, CH2.08, CH2.09, CH2.10.

Most of the knowledge and skills expectations are evaluated during the practical test portion.

Planning Notes

Materials required for Activity 7.1 include:

· nails

· salt

· test tubes and other glassware

· stoppers

· thermometers

· hot plates or Bunsen burners

· balances

· computer probes (optional)

Materials required for Activity 7.2 include:

· a selection of materials from Activities 1 to 5 depending on questions generated by the teacher

This activity is divided into two parts. In Activity 7.1, the teacher provides relatively simple materials and encourages students to consider a suitable experimental design involving the rusting of iron. This activity offers an opportunity to use different technologies such as calculator and computer interfaces and probes. Review safety procedures and make MSD Sheets available.

As Activity 7.2 is a summative test, it is recommended that teachers carefully consider the individual stations for clarity and replicability. Teachers should perform each task ahead of time to make sure the materials are suitable and the results clear. The method of recording answers is prepared and made clear to the students.

Prior Learning Required

Students were introduced to this assessment in Activity 2 and practised experimental design in Activities 2 and 5.

Teaching/Learning Strategies

7.1 Student Activity: Individual students design and perform an experiment, using nails, salt, water, and air, that allows them to determine which of at least two variables has the greater effect on the rusting of iron. Variables could include the concentration of salt, the type of salt (e.g. sodium chloride versus calcium chloride), the amount of air (e.g., concentration of dissolved oxygen), the type of gas (e.g., nitrogen, carbon dioxide, oxygen), and the temperature and quantity of the water. Some measurements could be taken using calculator or computer probes. The results are presented in a standard laboratory report.

Teacher Facilitation: Check experimental design for safety concerns only and not for feasibility as this is a test situation. The experimental design and experiment are completed during class time but additional materials may be brought from home. This activity may be started after Activity 5 or extended beyond the end of the unit to ensure completion.

7.2 Student Activity: Students complete a practical test based on skills and knowledge developed during this unit. Students move from station to station completing each task as instructed.

Teacher Facilitation: The tasks designed for this activity must present new situations in order to assess the understanding of concepts rather than the recall of previous experiences. Stations that require higher-order thinking skills are preferable to those of lower-order skills. As a result, stations are fewer in number but require more time for completion. Tasks could be designed around the following ideas:

· chemical properties of an element or compound;

· physical properties of an element or compound;

· determining density of an unknown substance and identifying substance from a data chart;

· density problems;

· molecular models;

· explanation of a phenomenon using the particle model;

· flame test to identify unknown compounds;

· identify spectrum using hand spectroscope (e.g., Na);

· Bohr/Rutherford diagrams;

· describing safe usage of material based on an MSDS;

· periodic table and predicting element properties based on position.

Two complete stations are provided as examples in the Attachment below.

Assessment/Evaluation Techniques

The methods used for evaluation follow from the class discussion in Student Activity 2.2.

Some instruments might include:

· Partial Rubric for Inquiry-Experimenting (TSM page xi - Phase 1)

· Checklist on laboratory procedure (rubric)

· Teacher evaluation of laboratory report (rubric)

· Teacher evaluation of practical test (marking scheme)

Accommodations

· Refer to TSM-Accommodations for Students with Special Needs.

· Students with impaired motor skills may make observations, predictions, and suggested modifications while an assistant performs the physical activity. This assistant should not be a class member due to the summative nature of the task. Alternatively, a different test time could be arranged.

Resources

Liem, T.K. Invitations to Science Inquiry. (See Unit Resources.)

Summerlin, L.R., C.L. Borgford, and J.B. Ealy. Chemical Demonstrations. A Sourcebook for Teachers. Volumes 1 and 2. Washington: American Chemical Society, 1988.

Attachment: Stations

Sample Station 1

Materials: 2 candles (one that is never lit), matches, goggles

Questions:

1. List three safety precautions related to the use of open flames.

2. Light the candle and record five observations, at least two of which describe chemical properties.

3. Classify your observations as chemical or physical properties.

4. What is the purpose of the candle that is never lit?

Sample Station 2

Materials: zinc, sulfuric acid, Bunsen burner, wooden splint, test tube, stopper, goggles

Questions:

1. List three observations of zinc that would help classify it as a metal.

2. Add a small piece of zinc to º test tube of dilute sulfuric acid and describe two signs of chemical change.

3. What gas is released? Explain how this was determined.

4. Sulfuric acid is a compound. How do you know this from your observations?

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