Ionic and Covalent Bonding
Concept Presentation
Presenter: Iris Lo
Instructors: Janine Extavour and Marty Zatzman
Date: Monday, July 12, 2010
Course: Honors Specialist General Science
Content Overview:
The Ionic and Covalent Bonding section of the SCH 3U course requires a review of Bohr’s model of the atom and the
process of ion formation as a starting off point. Students are taught the octet rule, how to draw Lewis diagrams for each
bond type (for the 2nd and 3rd period elements), the concept of electronegativity and how to predict bond type by using
electronegativity values. The section covers intramolecular bonding: namely, the bonding characteristics of ionic, polar
covalent and covalent bonds. Students gain an understanding of the properties of ionic and covalent compounds as well
as polar and non-polar molecules. Intermolecular bonding and metallic bonding are also discussed.
The focus of this concept analysis is to highlight common misconceptions and difficulties encountered by students and
to provide a suggested lesson sequence that outlines teaching strategies (including activities), and assessment and
evaluation tools to effectively teach and address the needs of students with different learning skills and abilities.
Specific Curriculum 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.
Common Misconceptions/Learning Difficulties:
1) a) “The Lewis structure of covalent compounds gives the shape of the molecule.”
b) Students have difficulties visualizing the 3D structure of molecules given a 2D representation.
 Reinforce that the Lewis structure only shows the linkage between atoms (Jenkins et al., 2002).
 To stress this, have students build molecular models for compounds containing single and multiple bonds to
give them a 3-dimensional representation of each molecule (Jenkins et al., 2002).
 To increase the level of student engagement, substitute molecular model kits with candy gumdrops as the
“atoms” and toothpicks as the “bonds” (Cherkas et al., 2002).
2) “Since both involve charges, the attraction between polar covalent molecules is the same as the attraction
between ions in an ionic compound” (Cherkas et al., 2002).
 Ensure students realize that the charges across polar covalent bonds are only partial charges.
 A way to clarify this misconception: Use the analogy of 3 divorced couples who are seeking therapy.
Couple #1
Lisa and Milhouse
(Ionic bond)
Analogy
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.
Couple #2
Buzz Lightyear and Jessie
(Polar covalent bond)
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.
Couple #3
Barbie and Ken
(Covalent bond)
They have equal attraction to each other and maintain their bond by having shared
custody of their son, Ben. Ben spends an equal amount of time with both parents.
3) “When predicting bond type using electronegativity, there is a sharp divide between ionic and covalent bonds.”
 Emphasize that the spectrum of electronegativity difference values is smooth. As the values go from 0 to
3.3, the bonds are coming increasingly more ionic and less covalent in nature. The ∆EN = 1.7 cutoff between
ionic and polar covalent bonds is only there as a guide for classification purposes (Cherkas et al., 2002).
 To reinforce this, use a model of a bonding continuum as a visual tool and a table organizer showing the
percent ionic character and percent covalent character for various electronegativity difference values. These
visuals enable students to gain an understanding that the spectrum is gradual (Cherkas et al., 2002).
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.”
 Students have a simplified view of the atom from Bohr Rutherford diagrams in grade 9 and 10 Science that
they bring with them to grade 11.
 When introducing the concept of bonding, it is important to make students aware that the models they are
using are simplified to help develop their understanding. In truth, chemists describe electrons in terms of
their energy and the probability of finding the electrons within a specific region of space about the nucleus,
a concept that is introduced and developed in grade 12 with the idea of orbitals (Jenkins et al., 2002).
 To introduce the idea of electron probability patterns, incorporate the following animations when discussing
ionic and covalent bonding: http://www.youtube.com/watch?v=_sUIhpULamM&feature=related (covalent
bonding) and http://www.youtube.com/watch?v=WXyFMJ0eJA0 (ionic bonding).
Place in the Curriculum:
Placement of the Unit in the Curriculum
It is suggested that the Matter, Chemical Trends and Chemical Bonding unit be the first unit in the SCH 3U course. The
rationale is that it covers concepts that form the underlying basis of all the other units in the course such as Chemical
Reactions, Quantities in Chemical Reactions, Solutions and Solubility and Gases and Atmospheric Chemistry. As a result,
a solid understanding is needed for full comprehension of the other units.
Also, this unit is a natural progression from the grade 9 and 10 Chemistry curricula as students have already been
introduced to atomic structure, patterns in the periodic table and ionic and covalent compounds. It allows teachers to
review and diagnostically assess student understanding from previous grades and then expand on those basic ideas with
ideas from the grade 11 curriculum. This natural progression gives the students increased confidence to tackle this
material as they have seen it before.
It is suggested that the Chemical Reactions unit be taught next. The reasoning is that, again, it picks up from where the
grade 10 Chemistry unit left off by expanding on balancing chemical equations and the types of chemical reactions, in
addition to introducing new concepts. As well, the Matter, Chemical Trends and Chemical Bonding unit ends with
naming (using the IUPAC nomenclature system) and writing chemical formulas of binary and polyatomic compounds, a
skill that is applied in the Chemical Reactions unit (i.e., when writing out chemical equations, predicting the product of
chemical reactions, etc). By having students apply this skill almost immediately in this second Chemical Reactions unit,
this skill is reinforced through more practice, retention of the material is increased and students begin to see its worth.
Placement of the Concept Within the Unit
It is suggested that the Matter, Chemical Trends and Chemical bonding unit begin by covering grade 9 and 10 Chemistry
review on the Bohr model of the atom, ion formation, and properties of ionic and molecular compounds as well as
introduce key concepts that will be used throughout this section (namely, the octet rule and drawing Lewis structures).
The rationale is to diagnostically assess what students know and also to ensure that students have a solid foundation of
these Chemistry basics before continuing on to more challenging ideas within the unit.
It is suggested to give students an overview of bonding so that they are given some context and to help organize the
ideas. Introduce, using a concept organizer, that bonding involves intramolecular, intermolecular and metallic bonds and
that within intramolecular and intermolecular bonding, there are sub-categories of bonds (i.e., ionic bonds, covalent
bonds, etc.). This is important so students are made aware that although the focus is on covalent and ionic bonds, other
types of bonding do exist, and will be discussed subsequently. Ending the unit with naming and writing chemical
formulas of compounds is suggested as it ties in very well with the second unit, Chemical Reactions.
Lesson Sequence:
Refer to Table 1.
Applications and Societal Implications:
1) Ions and the Human Body
 Humans depend on ions for their survival - they are essential for maintaining good health
 Ex. Ca2+ is needed for bone & teeth formation and Cl-, Mg2+, Na+, and K+ are major components of blood
(Jenkins et al., 2002)
2) Carbon Dioxide in Soft Drinks: A Covalent Compound
 Like a typical 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 the 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).
Annotated 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.

This teacher’s resource is excellent. It provides the same type of information as the Nelson Chemistry 11 teacher’s
resource (refer to the Nelson Chemistry 11 teacher’s resource analysis below for specifics) but does so more
effectively by going in more detail and by considering ways to teach the topic from various angles. Also, it
includes teaching strategies for supporting diverse student needs (ESL students, etc.)
2) Hand, J. (2010). Chemistry Games. Retrieved July 9, 2010, from
<http://www.mansfieldct.org/schools/mms/staff/hand/chemgames.htm>

This website is a useful resource as it provides pre-made matter, and ionic and covalent bonding review games
that are in Jeopardy, Who’s Wants to be a Millionaire, hangman, etc. format. These games can either be done as
a class or can be done individual by the student at home for their own review purposes.
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.

This teacher’s resource is helpful as background information, teaching suggestions (activities, extra resources,
effective ways to approach the lesson, tips and safety precautions for conducting labs), answers to lab/ textbook
questions and common student misconceptions and concrete ways to address these difficulties are provided.
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>

This website is a good resource as it provides lessons (including PowerPoint presentations), handouts, labs and
worksheets for grade 11 and 12 Chemistry. Handouts and worksheets are in pdf format, however, making it
more difficult to tweak for your own classes.
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/sc
ience/Chemistry%2520Demonstrations+water,+ebonite+rod,+hexane&cd=1&hl=en&ct=clnk&gl=ca>

This website is a useful resource as it provides many quick and good Chemistry demonstrations. The materials,
procedure and what should be observed is included for each demonstration. This is not to be shared with your
students as it would spoil the result of the demonstration.