1. The author taught a lesson on ionic and covalent bonding to a class of 26 high-achieving Year 9 students. 2. During the lesson, the students completed a worksheet in pairs to consolidate their understanding of the differences between ionic and covalent bonding and how this relates to substance properties. 3. An evaluation found that most students understood the concepts well after the lesson, though a later quiz showed some students still struggled with identifying mistakes in example dot-and-cross diagrams.

1. Materials Education Report
Teaching and Revision of Chemical Bonding
Nd60
April 23, 2014
Abstract
The concepts of ionic and covalent bonding underpin the teaching of iGCSE chemistry. Students often find it difficult
to remember and rationalise the various properties, and present their answers in the best way to achieve top marks.
I chose to use my teaching time to focus on highlighting the differences between these types of bonding and how this
manifests in the substance properties.
1 Background
I taught at The Perse School. The Perse is an indepen-
dent, selective, co-educational school which consistently
achieves very high grades. Last year 93% of the 145 iGCSE
chemistry students achieved an A/A*; 100% achieved A*
to C [1].
I taught a class of 26 Year 9 students who had just
started their iGCSE chemistry course. Although the class
were nominally a mixed ability class, the students were
generally A/A* students in accordance with the demo-
graphic of the school. The class were arranged in a seat-
ing plan which generally put weaker students near helpful
high-achieving students, and kept louder students apart.
I based my teaching on the Edexcel specification for
ionic and covalent bonding - see appendix A. I observed
the first lesson and then acted as a teaching assistant in
most of the others. In my fourth lesson I taught a 20
min section on covalent bonding, and in my sixth lesson I
taught a 1 hr 20 mis revision session to consolidate knowl-
edge of ionic and covalent bonding, structure and proper-
ties.
2 Previous Treatment of the Topic
The Perse provides teachers with a Scheme of Learning
as a framework (see appendix B). The exact methods and
order of delivering material is left to each teacher’s discre-
tion.
Previously Dr Khimyak had taught dot-and-cross di-
agrams by showing students examples on the board and
then giving them a worksheet. She also had not previously
pulled together properties and examples of ionic and co-
valent substances into one table (see section 5.2), which I
chose to do.
3 Project Topic
From my previous experience of tutoring ionic and cova-
lent bonding and a discussion with Dr Khimyak we de-
cided that I could focus on the confusion between the dif-
ferent types of bonding. Often students find it difficult
to justify the properties exhibited by compounds, espe-
cially when referring to intra- and inter-molecular bond-
ing. There is also confusion about the relative strength of
bonds (ionic or covalent) and intermolecular forces (such
as van der Waals’ forces).
For my special project I ran a revision session on
these topics. The objective was to solidify their knowl-
edge through a mixture of class discussion, a worksheet
which they completed in pairs and a review of the work-
sheet. This worksheet was designed to also act as a good
revision resource for their upcoming test, and eventually
for their iGCSE exams.
I considered two other options before settling on a work-
sheet oriented lesson: a dictated class and an interactive
class. From observation of previous lessons I had seen how
quickly the class lost focus whenever they had to copy
down dictated notes. Although this would leave them with
a good resource it would not improve their knowledge. A
more interactive lesson would engage the class however it
would be more difficult to leave them with useful revision
material. The class, and particularly the weaker students,
were also likely to become less focused if given more scope
for conversation. Thus I decided a worksheet was the best
option.
4 Planning
In appendices C & D I have included lesson plans for the
two lessons I taught.
The first lesson was a short 20 min section on covalent
bonding. I prepared templates of covalent molecules, such
as those shown in appendix E. I gave the 13 listed on the
specification to each table, along with coloured counters to
represent electrons. They used these to decide where the
electrons went, check with me or Dr Khimyak and then
draw it out in their exercise books.
For the special project lesson I prepared two online
quizzes: one to be taken at the beginning of the lesson
and one at the end. These are included as appendices F
& G and were made and run using the online resource
Socrative [2]. The main section of the lesson was based on
filling in a worksheet. I have included the blank copy given
to the students and the filled copy I used as appendices H
& I.
1

2. 6.2 Dot-and-Cross diagram lesson Nd60
5 Execution
5.1 Dot-and-Cross diagram lesson
I ran a 20 min section at the beginning of a Tuesday af-
ternoon lesson. I gave out the molecule sheets and the
counters as the students entered however they were still
distributing counters when I began the lesson.
First I gave one example of covalent bonding on the
board, asking the students what I needed to think about:
• how many electrons the atoms had to start with
• how many each atom needed for a full outer shell
• therefore how many each atom needed to share
They then told me where the electrons needed to go and
I asked them what we needed to check:
• check each atom was supplying the correct number of
electrons
• check that each atom now appeared to have a full
outer shell
I wrote up the steps they needed to think through on the
board so they could refer to them later.
I explained what the counters and molecule sheets were
for, told them to draw out the molecules in their exer-
cise books when they had checked they were correct and
let them start the exercise. I spent the next 15 mins walk-
ing around the class checking their dot-and-cross diagrams
and answering their questions.
5.2 Ionic and Covalent Bonding and
Structure revision lesson
Before the lesson I collected the school’s Chromebooks
with Dr Khimyak and wrote the relevant log in details for
the Socrative quiz on the board.
When the students arrived they collected a Chromebook
each, logged in and began the quiz. I could follow on my
computer who had completed the quiz and stopped them
after 15 mins. I then discussed the major properties of
ionic and covalent compounds with the class by asking
questions and making sure that everyone was volunteering
answers.
I gave the students the worksheet and let them start to
fill it in. They had quite a few individual questions and,
after 25 mins, I stopped them. I then went through the
worksheet and filled in the answers they gave me on the
board. I ensured that all of the individual questions I had
been asked were addressed in case other students had also
been confused. I encouraged them to check their worksheet
against the one on the board.
Finally I set them another 10 min quiz.
6 Evaluation
6.1 Observations
I spent one lesson observing the class and most others
helping as a teaching assistant. This gave me time to learn
from Dr Khimyak’s teaching style, engage with the stu-
dents and learn their individual strengths and weaknesses.
Below I have pinpointed my major observations.
• Dr Khimyak said ‘Thank You’ when students were
loud and disruptive. This made it clear to them to
be quiet without being confrontational. They became
quiet quickly.
• When asking questions she would wait for most stu-
dents to put their hands up. This encouraged them
all to think about the question. She then took most
people’s answers, concisely reviewing the topic and
ensuring all students were involved.
• Some students were more high-achieving than others.
I stretched these students on by asking them harder
questions on or related to the topic.
• Some students believed they were not able to answer
the questions despite having the requisite knowledge.
I asked them pointed questions which they could an-
swer and showed them that they had been able to
work to the answer all along. This stopped them from
distracting each other and encouraged them to do the
rest of the work.
• One student was particularly distracted by his friend
but was struggling with the work. Each lesson I made
a point of trying to spend more time with him how-
ever altering the seating plan would help with this. I
spoke to Dr Khimyak about this and this will happen
with the next new seating plan.
6.2 Dot-and-Cross diagram lesson
My feedback is from teacher and student feedback, and
watching them attempt similar questions in later lessons.
I felt the lesson went well. The students generally
worked well and most quickly learned how to tackle the
problem. Some students later got distracted when they
felt they understood it but were keen to show me what
they had done and ask for harder examples when I came
to check their work. We also discussed the shapes of the
molecules.
Dr Khimyak’s feedback was very positive. She felt the
students had learned quickly and that the exercise I had
developed was very effective. In her previous lesson she
had introduced dot-and-cross diagrams but the students
left confused. I felt this exercise worked as when the stu-
dents made a mistake they did not become disheartened
by having to draw the molecule again; instead just re-
arranging counters. Dr Khimyak suggested I should have
handed out all the materials before the lesson to save time.
This had not been possible as a class was using the room
before the lesson but in future I would take this on board.
The students seemed very positive about the exercise.
One student told me that she felt it was “fun, and ed-
ucational”. In the revision class, three weeks after the
dot-and-cross diagram session, no students appeared to
have trouble with the dot-and-cross diagram included on
the worksheet. However only 57% of them got a question
on the Socrative quiz correct which showed an incorrect
dot-and-cross diagram for N2 (see figure 1) and asked the
students to choose what was wrong with it, from:
• Too many electrons being shared
• Too many lone pairs (electrons which are not shared)
2

3. Nd60
• Not enough electrons being shared
• Not enough lone pairs (electrons which are not
shared)
Figure 1: Incorrect N2 dot-and-cross diagram
The exercise taught them to draw their own dot-and-cross
diagrams, the skill tested in the exam, while the question
asked them to spot errors. It was not a good test of their
knowledge but still implies that this topic needs to be
reviewed.
I took away from this lesson the importance of good
preparation and saw that the students responded well to
interactive work.
6.3 Ionic and Covalent Bonding and
Structure revision lesson
My feedback on this lesson is more quantitative, however
I also received some teacher and student response.
Dr Khimyak was pleased with how the lesson went and
impressed by the worksheet I had produced. The students
appeared to enjoy this lesson less than my last one as it
involved more writing. They were all very keen to answer
questions at all times but by the time of the final quiz
they were somewhat tired and distractable. Two students
closed each other’s quizzes before they were completed
rendering their data invalid. A small number of other stu-
dents also focused on these questions less than the first
quiz which may have affected their results.
I set two quizzes, appendices F & G. I also asked three
iGCSE and one AS student that I know to fill in the
quizzes to establish whether one is more difficult that the
other. This is a smaller control sample size than I would
have liked and I should have carried this out before the
session and designed equivalent tests. I also made a mis-
take when setting the quizzes as the students were not
able to choose multiple answers on the Socrative website.
The boxplots below indicate the control results, figure 2,
class results, figure results, and class results when a scaling
factor is applied to Quiz 1.
Scaling Factor =
Control median for Quiz 2
Control median for Quiz 1
(1)
As the control group results indicate that the second
quiz was harder than the first, including the scaling fac-
tor indicates an increase in the class results. I included
more short answer questions in the second quiz than the
first which the students found harder than multiple choice
questions. It appears that the students performed better
after the lesson, however I would be more confident if the
quizzes had been better matched.
0
20
40
60
80
100
1 2
PercentageScore/%
Quiz
Boxplot of Control Results
Figure 2: Boxplot indicating the spread of data in the
control group for each quiz
0
20
40
60
80
100
1 2
PercentageScore/%
Quiz
Boxplot of Class Results
Figure 3: Boxplot indicating the spread of results in the
class for each quiz
If I were to repeat the lesson I would keep the general
outline the same. I feel the worksheet was very useful and
this is seen in the comparison of results. I also have used a
similar technique with students I have tutored before and
found it useful as a revision tool.
I would, however, limit the time for the quiz and insist
upon silence as not doing so led to some students distract-
ing others. I would also follow this session with practice on
short answer questions. These are prevalent in the exam
and serve as a good way to solidify how the structure leads
to the property.
7 Conclusions
In this project I set out to learn how to teach a class. I
found that it was paramount to consider:
1. Whether the task would engage the students and thus
hold their attention
2. How well they would understand the material at the
time
3

4. REFERENCES Nd60
0
20
40
60
80
100
1 2
PercentageScore/%
Quiz
Boxplot with Quiz 1 Scaled
Figure 4: Boxplot indicating the spread of data in the class
for each quiz after Quiz 1 was scaled
3. How well they would retain the information and un-
derstand the material weeks or months later
In my special project I aimed to improve the students’
understanding at the time of the lesson whilst also ensur-
ing the material would be better understood in the future,
and to provide them with a resource to help with this.
From observation of the students I found that they were
most engaged and learned most when they were actively
working as it gave them time to consider the problem
themselves.
On reflection the results indicate an improved under-
standing of the topic after the lesson. I was not able to
test whether this lesson helped the students to retain the
information over a longer timespan.
References
[1] iGCSE level results by subject in 2013 - Year 11.
(2013)
Available: http://www.perse.co.uk/upper/curriculum/exam-
results/. Last accessed 18th Mar 2014.
[2] Socrative. (2014)
Available: http://www.socrative.com/. Last accessed
18th Mar 2014.
4

5. UG029853 –– Specification –– Edexcel International GCSE in Chemistry (4CH0) ––
Issue 4 –– November 2011 © Pearson Education Limited 2011
6
f) Ionic compounds
Students will be assessed on their ability to:
1.28 describe the formation of ions by the gain or loss of electrons
1.29 understand oxidation as the loss of electrons and reduction as the gain of
electrons
1.30 recall the charges of common ions in this specification
1.31 deduce the charge of an ion from the electronic configuration of the atom
from which the ion is formed
1.32 explain, using dot and cross diagrams, the formation of ionic compounds by
electron transfer, limited to combinations of elements from Groups 1, 2, 3
and 5, 6, 7
1.33 understand ionic bonding as a strong electrostatic attraction between
oppositely charged ions
1.34 understand that ionic compounds have high melting and boiling points
because of strong electrostatic forces between oppositely charged ions
1.35 understand the relationship between ionic charge and the melting
point and boiling point of an ionic compound
1.36 describe an ionic crystal as a giant three-dimensional lattice
structure held together by the attraction between oppositely
charged ions
1.37 draw a diagram to represent the positions of the ions in a crystal of
sodium chloride.
Nd60
A Edexcel iGCSE Chemistry Specification: Ionic and Covalent Bonding
5

6. UG029853 –– Specification –– Edexcel International GCSE in Chemistry (4CH0) ––
Issue 4 –– November 2011 © Pearson Education Limited 2011
7
g) Covalent substances
Students will be assessed on their ability to:
1.38 describe the formation of a covalent bond by the sharing of a pair of
electrons between two atoms
1.39 understand covalent bonding as a strong attraction between the bonding
pair of electrons and the nuclei of the atoms involved in the bond
1.40 explain, using dot and cross diagrams, the formation of covalent compounds
by electron sharing for the following substances:
i hydrogen
ii chlorine
iii hydrogen chloride
iv water
v methane
vi ammonia
vii oxygen
viii nitrogen
ix carbon dioxide
x ethane
xi ethene
1.41 understand that substances with simple molecular structures are gases or
liquids, or solids with low melting points
1.42 explain why substances with simple molecular structures have low melting
and boiling points in terms of the relatively weak forces between the
molecules
1.43 explain the high melting and boiling points of substances with giant covalent
structures in terms of the breaking of many strong covalent bonds
1.44 draw diagrams representing the positions of the atoms in diamond
and graphite
1.45 explain how the uses of diamond and graphite depend on their
structures, limited to graphite as a lubricant and diamond in cutting.
h) Metallic crystals
Students will be assessed on their ability to:
1.46 understand that a metal can be described as a giant structure of positive
ions surrounded by a sea of delocalised electrons
1.47 explain the electrical conductivity and malleability of a metal in terms of its
structure and bonding.
Nd60
6

7. 9.5BondingandStructure
WeekTopicLearningoutcomesActivitiesResources
1IonsandIonic
Bonding
Studentswillbeassessedontheirabilityto:
1.28describetheformationofionsbythe
gainorlossofelectrons
1.30recallthechargesofcommonionsin
thisspecification
1.31deducethechargeofanionfromthe
electronicconfigurationoftheatomfrom
whichtheionisformed
1.32explain,usingdotandcrossdiagrams,
theformationofioniccompoundsby
electrontransfer,limitedtocombinations
ofelementsfromGroups1,2,3,and5,6,
7
1.33understandionicbondingasastrong
electrostaticattractionbetweenoppositely
chargedions
1.34understandthationiccompounds
havehighmeltingandboilingpoints
becauseofstrongelectrostaticforces
betweenoppositelychargedions
1.35understandtherelationship
betweenionicchargeandthemelting
pointandboilingpointofanionic
compound
Activities:
●Drawdot/crossdiagramsofelectron
transferandionformationfor
combinationsofelementslisted.Work
outtheformulaeandnameofthe
compoundsformed.
●Drawacartoonofionicbonding,e.g.
whensodiummetchlorine.
●Predicttheformulaeofnamed
compoundsusingatableofcommon
ions.
●Learntheformulaandchargeofions:
games,e.g.IonBingo
●Drawconclusionsabouttheproperties
ofsubstancesthathavegiantionic
structures.
●Makeamodelanddrawadiagramofa
sodiumchloridelattice.
●WatchICTanimationoflattice
formation:enactlatticeformation.
●Interpretmeltingpointdatatoderive
linkbetweenionicchargeandmelting
point.
Demonstration:
●Combinationofelements:aluminium
withiodine,magnesiumwithsulfur.
Classpractical:
321Migrationofcolouredions–
KMnO4
322Electrolysisofmoltenzinc
StudentBookPages17-19,25–27
p.22Q3;p.32Q.3
FpS:Bonding
G&T:10Bondingmodels
11Ionicbonding
15Ionicsudoku
Nd60
B Extract of Scheme of Learning
7

8. Lesson Plan
Dot-and-Cross Diagrams
Nd60
Febuary 4, 2014
1 Objectives
To build upon the introduction to covalent bonding in the previous lesson by letting the students attempt to complete
dot-and-cross diagrams themselves using drawn molecules on cards and counters. Aim to show the conservation of
initial electrons and the effective filling of the outer shell on each atom in the molecule via shared pairs. Also reference
the shape of the molecules and the influence of the lone pairs on this shape to the higher achieving students.
2 Time
20 mins
3 Materials
Six copies of each of the 13 molecules listed in the specification on paper (one set per table), paper counters to
represent electrons (two different colours), exercise books to draw final electronic structure.
4 Procedure
1. Run through the thought process behind placing electrons on the dot-and-cross diagram for HCl by asking the
class questions and writing the important points on the board.
• How many electrons does H have on its outer shell?
• How many more does it want for a full outer shell?
• How many electrons does Cl have on its outer shell?
• How many more does it want for a full outer shell?
• How many do they each share?
• Place other electrons on outer shell
• Check that each atom is contributing the number of electrons it started with
• Check that each atom now has a full outer shell
2. Allow the students 15 mins to attempt the others themselves or in pairs. Tell them to draw them in their exercise
books when they are correct. Walk around the class helping the weaker students and stretching the brighter
students by discussing the impact of electrons and lone pairs on shape.
3. Hand over class to Dr Khimyak.
Nd60
C Dot-and-Cross Diagram Lesson Plan
8

9. Lesson Plan
Ionic and Covalent Bonding and Structure Revision
Nd60
Febuary 25, 2014
1 Objectives
• To solidify the knowledge from the previous half term on ionic and covalent bonding and structure.
• To highlight problem areas such as the difference between weak intermolecular forces and strong interatomic
bonds.
• To leave the students with a useful worksheet to revise from in future.
• Quizzes at beginning and end to test progress over lesson.
2 Time
1 hr 20 mins
3 Materials
Chromebooks for quizzes, worksheets.
4 Procedure
1. (15 mins) Students collect Chromebooks and fill in first quiz on the Socrative website.
2. (10 mins) Discussion on ionic and covalent bonding and structure and the resulting properties through questions
to the class. Ensure that majority of students have answered questions and that all are engaged.
3. (25 mins) Give out worksheets and let students attempt to fill in answers. Walk around the class and help with
questions.
4. (10 mins) Project blank worksheet on board and get the students to tell me what the answers are so that they
can all check all of their answers. Explain each answer after it is given to ensure a succinct answer is heard by
the students.
5. (15 mins) Students use the Chromebooks again to carry out a second quiz on the Socrative website.
6. (5 mins) Pack away Chromebooks.
Nd60
D Ionic and Covalent Bonding and Structure Revision Lesson Plan
9

10. Nd60
E Examples of Dot-and-Cross Molecule Worksheets
10

11. 1. Ionic and Covalent Bonding
1. Please state your name (e.g. Smith, John)
2. An ionic bond is between:
a. Two non-metals
b. A metal and a non-metal
c. Two metals
3. What happens when Sodium and Chlorine react to form bonds?
a. Sodium loses an electron, Chlorine gains an electron
b. Sodium gains an electron, Chlorine loses an electron
c. Sodium and Chlorine each share one electron with the other atom
d. Sodium loses two electrons, Chlorine gains two electrons
4. Which statement is correct?
a. Sodium Chloride has a low melting point because of its strong
ionic bonds which are caused by electrostatic interactions
between the ions
b. Sodium Chloride has a high melting point because of its strong
ionic bonds which are caused by electrostatic interactions
between the ions
c. Sodium Chloride has a low melting point because of the weak
interatomic forces between the ions
d. Sodium Chloride has a high melting point because of the weak
interactomic forces between the ions
e. Sodium Chloride has a low melting point because of its strong
covalent bonds
5. When can ionic compounds conduct electricity?
a. When solid, liquid or dissolved
b. Only when solid
c. Only when liquid
d. Only when dissolved
e. Only when liquid or dissolved
6. Describe how a covalent bond forms and how it holds the atoms
together.
7. Which of these contain covalent bonds?
a. Carbon Dioxide
b. Potassium Oxide
Nd60
F First Quiz
11

12. c. Diamond
d. Chlorine gas
e. Aluminium Chloride
8. Why can graphite conduct electricity?
9. Which of these statements are correct? (Hint: more than one is correct)
a. Diamond is hard because of the strong covalent bonds between
the atoms
b. Diamond can conduct electricity because the electrons are free to
move
c. Diamond is used as a lubricant
d. Diamond has a high melting point
e. Diamond is made of only Carbon atoms
10. When Calcium reacts with Oxygen the Calcium atom becomes an ion. Is
it a cation or an anion and what is its charge?
a. Cation, charge 2-
b. Anion, charge 2-
c. Cation, charge 2+
d. Anion, charge 2+
Nd60
12

13. 2. Ionic and Covalent Bonding
1. Please state your name (e.g. Smith, John)
2. A compound is a gas at room temperature. Which type of compound
would you expect it to be?
a. Ionic compound
b. Giant covalent compound
c. Simple covalent molecule
3. How many bonds does each Carbon atom make in Diamond?
a. 1
b. 2
c. 3
d. 4
e. 5
4. Explain why ionic compounds such as Sodium Chloride are soluble in
water.
5. A substance has a melting point of 2000 degrees celsius and does not
dissolve in water. What sort of structure is it?
a. Giant covalent
b. Giant ionic
c. Simple covalent
6. Silicon and Oxygen react to form Silicon Dioxide. Which set of properties
would you expect this compound to have?
a. High melting point, insoluble in water, doesn't conduct electricity
even when molten
b. Low melting point, insoluble in water, doesn't conduct electricity
even when molten
c. Low melting point, soluble in water, doesn't conduct electricity
even when molten
d. Low melting point, soluble in water, conducts electricity when
molten
e. High melting point, soluble in water, conducts electricity when
molten
7. Why is graphite used as a lubricant?
8. Explain why simple covalent molecules such as water have low melting
points despite containing strong covalent bonds.
Nd60
G Second Quiz
13

14. 9. What is wrong with this dot-and-cross diagram for Nitrogen gas?
a. Too many electrons being shared
b. Too many lone pairs (electrons which are not shared)
c. Not enough electrons being shared
d. Not enough lone pairs (electrons which are not shared)
10.Describe the structure of an ionic crystal.
Nd60
14

15. Nameof
compound
FormulaDiagram
Ionicor
covalent?
Simplemoleculeor
giantlattice?
Meltingpoint:
highorlow?
Conductelectricity
whensolid,liquid,
gasordissolved?
Solublein
water?
Cl2
Carbon
Dioxide
Calcium
Fluoride
Graphite
Nd60
H Blank Worksheet
15

16. Nameof
compound
FormulaDiagram
Ionicor
covalent?
Simplemoleculeor
giantlattice?
Meltingpoint:
highorlow?
Conductelectricity
whensolid,liquid,
gasordissolved?
Solublein
water?
ChlorineCl2CovalentSimpleMoleculeLowNoNo
Sodium
Chloride
(Salt)
NaClIonicGiantLatticeHighLiquid,dissolvedYes
Carbon
Dioxide
CO2CovalentSimpleMoleculeLowNoNo
DiamondCovalentGiantLatticeHighNoNo
Calcium
Fluoride
CaF2IonicGiantLatticeHighLiquid,dissolvedYes
GraphiteCovalentGiantLatticeHighYesNo
Nd60
I Filled Worksheet
16