CONCEPT PRESENTATIONIONIC AND COVALENT

BONDING (SCH3U)

Presenter: Iris Lo Instructors: Janine Extavour & Marty Zatzman, OISE/UT

Overview

Curriculum Expectations Common Misconceptions Curriculum Placement 4 Day Lesson Sequence Applications Teacher Resources

Curriculum Expectations

Specific Expectations: B2.1 – Use appropriate terminology related to chemical

trends and chemical bonding, including, but not limited to: atomic radius, effective nuclear charge, electronegativity, ionization energy and electron affinity.

B2.4 – Draw Lewis structures to represent the bonds in ionic and molecular compounds.

B2.5 - Predict the nature of a bond (e.g., non-polar covalent, etc.) using electronegativity values of atoms.

B2.6 - Build molecular models, and write structure formulae, for molecular compounds containing single and multiple bonds and for ionic crystalline structures.

B3.4 – Explain the differences between the formulation of ionic bonds and the formation of covalent bonds.

B3.5 – Compare and contrast the physical properties of ionic and molecular compounds.

Bonding Analogy

Welcome to the Dr. Phil Show!

Today we will be counseling 3 divorced couples Lisa Simpson and Milhouse Buzz Lightyear and Jessie Ken and Barbie

Let’s have a look at how they interact to determine what is ‘bonding’ them together before we begin!

Couple #1

Milhouse is still very attracted to Lisa while she feels no attraction.

Milhouse has taken sole custody of their child, Nelson, a factor that keeps them bonded together.

Which bond does this couple represent (ionic, polar covalent or non-polar covalent)?

Couple #2

Buzz Lightyear is more attracted to Jessie than she is to him.

Although this attraction is unequal, they Do still share a love for one another.

They have joint custody of their son, Buzz Jr, with Buzz Jr. spending time primarily with his father.

Which bond does this couple represent (ionic, polar covalent or non-polar covalent)?

Couple #3

This couple has equal attraction to each other

They maintain their bond by having shared custody of their son, Ben.

Ben spends an equal amount of time with both parents.

Which bond does this couple represent (ionic, polar covalent or non-polar covalent)?

Common Student Misconception #1

“Since both involve charges, the attraction between polar covalent molecules is the same as the attraction between ions in an ionic compound”

Solutions: Emphasize that charges across polar covalent

bonds are only partial charges Use the Dr. Phil bonding analogy

Common Student Misconception #2

“The Lewis structure of covalent compounds gives the shape of the molecule.”

Solutions: Reinforce that Lewis structure only shows

atom linkage Have students build molecular models

(modification: use gumdrops and toothpicks)

Common Student Misconception #3

“When predicting bond type using electronegativity, there is a sharp divide between ionic and covalent bonds.”

Solutions: Emphasize that the spectrum of electronegativity

difference values is smooth Reinforce using a model of a bonding continuum and a

table organizer showing percent ionic/covalent character for various ∆EN values

Common Student Misconception #4 “The modern view of the atom is one in

which the electrons circle the nucleus in fixed orbits, like the planets orbiting the sun.”

Solutions: Make students aware that the models they are

using is simplified Chemists describe electrons in terms of energy and

probability of finding electrons within a region of space Use videos to help students visually

Covalent Bonding Video Ionic Bonding Video

Curriculum Placement of the UnitMatter, Chemical Trends and Chemical Bonding

unit: Matter, Chemical Trends and Chemical bonding

unit is placed as the1st unit of the course Covers underlying basis of all other units Natural progression from grade 9 and 10 Chemistry

Chemical Reactions suggested to be the 2nd unit Natural progression from grade 10 Chemistry Natural progression from Unit 1 - writing chemical

formulas and naming of compounds needed for writing chemical equations, predicting chemical reaction products, etc.)

Concept Placement Within the Unit Placed after periodic trends and before writing chemical formulas

and naming compounds

Suggested order of the chemical bonding section:

1) Review:Bohr model of the atom, ion formation, properties of ionic and molecular compounds

2) Introduce key underlying concepts: Octet rule, Lewis structures

3) Introduce bonding overview:To give students some context

4) Intramolecular bonds: Ionic and covalent bonding

5) Intermolecular and Metallic Bonding

Bonding Overview

4 Day Lesson Sequence

Day 1: Review & Classifying Chemical Compounds

PowerPoint presentation:Bohr model of the atomDrawing Lewis structures Properties of ionic and covalent compounds.

Demo: Test and compare the conductivity of salt solution and sugar solutionSafety: Use low-voltage conductivity apparatus

Group Activity: Bond With a ClassmateStudents act as positive and negative ions and form bonds with their peers.

Introductory activity for day 2.

Assessment:

Informal question and answer (diagnostic)

Lewis structure and Properties of Ionic/Covalent Compounds worksheet

Predict, Observe, Explain Activity

Bond With a Classmate Activity: Your Thoughts?

In your table groups, discuss:

a) Pros/cons of this activity?

b) Ways to modify this activity for:

-Different grade levels

-Different streams (i.e. academic, applied, etc.)

Day 2: Introduction to Bonding PowerPoint presentation:

Octet ruleElectronegativity (including its periodic trend)Bonding continuum/characteristics of ionic, polar covalent,

covalent bonds  Video Clip on Bonding/Electronegativity

Role-Play:

Use the analogy of 3 couples going through relationship counseling to represent ionic, polar covalent and covalent bonding.

  Assessment:

Informal question and answerDetermine Bond Type Using Electronegativity worksheetObservation & feedback

Day 3: Ionic and Covalent Bonding

Ionic Bonding PowerPoint presentation/Chalk and Talk:

Formation of ions,Transferring single /multiple electrons & bonding involving > 2 ions (shown using Lewis

structures/structural formulas),Properties of ionic compounds.

Demo: Poker chips used to simulate ionic bonding.

Video Clip: Ionic Bonding

Covalent Bonding PowerPoint presentation (continuation):

Single and multiple covalent bonding (shown using Lewis structures/structural formulas)

Coordinate covalent bonds

Exceeding the octet rule

Properties of covalent compounds

Compare/contrast ionic and covalent compounds.

Demo: Poker chips used to simulate covalent bonding.

Video Clip: Covalent Bonding

Day 3 (Cont’d)

Assessment:Informal question and answerDrawing Lewis and Structural Diagrams of Ionic and Covalent Compounds worksheet

Day 4: Polar Covalent Bonding

PowerPoint presentation:

Polar covalent bonding (shown using Lewis structures and structural formulas)

Polar/non-polar molecules, partial charges, and overall polarity

Summary of all 3 bonds

Demo:

Place a charged ebonite rod next to water and then hexane. Water (polar) is attracted to the rod, hexane is not (non-polar)

Safety: Hexane is a flammable liquid – do not place near open flames.

Do not directly smell it. Use in well-ventilated area.

Class discussion: Applications and societal implications.

  Lab: Gumdrop Molecular Models

Build molecular models and draw the Lewis diagram, structural formulas and predicted shape of molecule for ionic and covalent compounds (Cherkas et al., 2002).

Safety: Students must not eat the candy if they are working with it in the lab.

Day 4 (Cont’d)

Assessment and Evaluation:Informal question and answer

(assessment) Polar Covalent Bonding worksheet (assessment)

Predict, Observe, Explain Activity (assessment) Learning skills rubric (assessment)

Lab worksheet (evaluation)

Concept Applications

1) Ions and the Human Body Humans depend on ions for their survival

they are essential for maintaining good health

2) Carbon Dioxide in Soft Drinks: A Covalent Compound CO2 is somewhat soluble in water,

especially at high pressures which is why soft drinks are bottled under pressure (Mustoe et al., 2001).

When you open a bottle of pop, some of the CO2 comes out of solution due to its low solubility (Mustoe et al., 2001).

3) Application of Water Polarity: Microwave Ovens Water is a polar molecule that is a good

absorber of microwaves (Rayner-Canham, et al., 2002).

The energy is converted into heat to warm up food (Rayner-Canham, et al., 2002).

Resources

1) Nelson and McGraw-Hill Ryerson Chemistry 11 Teacher’s Resource

Both provide: background info teaching suggestions (activities, tips/safety

precautions for conducting labs, effective ways to approach the topic)

answers to lab/textbook questions common misconceptions and solutions

Prefer McGraw-Hill Ryerson Teacher’s Resource more detailed, includes strategies to support diverse

student needs (ex. ESL students, etc.)

Resources (cont’d)

2) Chemistry Games: J. Hand’s class website Provides pre-made review games

3) Chalkbored: J. Schneider’s class website Provides PowerPoint presentations, handouts, labs,

worksheets for grade 11 and 12

4) Chemistry Demonstrations: T. Sperring’s website Provides many quick Chemistry demos Materials, procedure and what should be observed are

included

References

1) Cherkas, A., Freure, C., George, T., Ivanco, J., Kisway, L., Plavetic, S.J., Stewart, J., and G. Wisnicki. (2002). McGraw-Hill Ryerson Chemistry 11 Teacher’s Resource. Toronto: Mc-Graw-Hill Ryerson.

2) Hand, J. (2010). Chemistry Games. Retrieved July 9, 2010, from <http://www.mansfieldct.org/schools/mms/staff/hand/chemgames.htm>

3) Jenkins, F., van Kessel, H., Davies, L., Lantz, O., Thomas, P., and D. Tompkins. (2002). Nelson Chemistry 11. Toronto: Nelson

Thomson Learning.

4) Jenkins, F., van Kessel, H., Davies, L., Sanader, M., Tompkins, D., Lantz, O., and S. Haberer. (2002). Nelson Chemistry 11

Teacher’s Resource. Toronto: Nelson Thomson Learning.

5) Mustoe, F., Jansen, M., Doram, T., Ivanco, J., Clancy, C., and A. Ghazariansteja. (2001). McGraw-Hill Ryerson Chemistry

11. Toronto: McGraw-Hill Ryerson Limited.

6) Rayner-Canham, G., Damju, S., and U. Goering-Boone. (2002). Addison Wesley Chemistry 11. Toronto: Addison Wesley.

7) Schneider, J. (2009). Chalkbored: Chemistry 11. Retrieved July 9, 2010, from <http://www.chalkbored.com/lessons/chemistry-11.htm>

8) Sperring, T. (2000). Chemistry Demonstrations. Retrieved July 9, 2010, from

<http://webcache.googleusercontent.com/search?q=cache:vRVGMG9e6HcJ:alex.edfac.usyd.edu.au/methods/scien

ce/Chemistry%2520Demonstrations+water,+ebonite+rod,+hexane&cd=1&hl=en&ct=clnk&gl=ca>