Weekly Plan 7
Covalent bonding
Student book links
Specification links
Link to GCSE specification
Suggested time allowed:
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Five hours
1.2.8–10
1.2.16
1.2.2 (e)–(j)
1.2.2 (q)–(s)
Covalent bonding
Properties of simple covalent
compounds
Suggested teaching order
1.
2.
Learning outcomes
Define covalent bonding including multiple bonds.
Draw dot-and-cross diagrams for simple molecules – e.g. H2,
Cl2, HCl, H2O, NH3, CH4, O2, N2, CO2.
Dative covalent bonding as in the ammonium ion
Dot-and-cross diagrams for some molecules that do not obey
the octet rule – e.g. BF3 and SF6
Electron pair repulsion theory
The shapes and bond angles in some simple molecules and
ions
Students should be able to:
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Describe a covalent bond as a shared pair of electrons.
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Describe single and multiple covalent bonding.
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Use dot-and-cross diagrams to represent covalent bonding.
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Describe dative covalent bonding.
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Describe examples of compounds that do not obey the octet rule.
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Explain how the shape of a simple molecule is determined.
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State that lone pairs of electrons repel more than bonding pairs.
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Explain and predict the shapes of – and bond angles in – molecules and ions.
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Describe the structures of simple covalent molecules.
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Explain the physical properties of simple covalent compounds.
3.
4.
Key words
How science works
Coordinate bond
Covalent bond
Dative covalent
Lone pair
Learning styles (S = Starter activities, M = Main activities, P = Plenary activities)
Kinaesthetic
Activities M1–M3
Activities P1–P3
Interpersonal
Activity S1
Activities M1–M3
Activities P1&P3
5.
6.
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Giant covalent lattice
Simple molecular lattice
Molecule
Auditory
Activities S1&S2
Activity P1
Lesson time allocated:
HSW 3D molecular shapes
HSW 1 Use models to develop and modify scientific
explanations.
ICT activities
Visual
Activity S3
Activities M1–M3
Activity P3
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Research other dative covalent molecules.
PowerPoint presentations to show atoms coming together to
form covalent molecules
Wikipedia: Read about covalent bonding
© Pearson Education Ltd 2008
This document may have been altered from the original
1
Weekly Plan 7
Suggested starter activities
Equipment
Teacher notes
1. Brainstorm how two atoms that both need to gain electrons
can achieve stability.
Ascertain how much the students remember from GCSE.
2. Having talked about discrete, simple molecules, ask the
students to predict melting points, solubility and conduction of
electricity.
This will also revise the same properties for giant ionic
structures.
3. Do a quick demonstration of the sublimation of iodine – a
simple covalent molecule.
Two or three crystals of iodine in a large
flask
Risk assessment. This demonstrates that very few iodine
crystals produce lots of iodine vapour.
Suggested main activities
Equipment
Teacher notes
1. Having introduced the topic and studied the first few dotand-cross diagrams, ask the students (in pairs) to draw other
examples of covalent bonding.
The students will probably need some help before going on
to multiple bonds.
2. Practical Activity 10: Investigating the relationships between
bonding, structure and physical properties in substances
See practical activity worksheet.
3. Let them make the molecular shapes using one of the
various molecular model kits (or balloons!).
Molecular model kits or balloons
The students can even estimate bond angles and suggest
names for the shapes. Larger balloons could represent lone
pairs.
Suggested plenary activities
Equipment
Teacher notes
1. Let them chose two s- or p-block elements at random and
suggest the name, formula and type of bonding.
Element cards
Be aware of the students drawing two metals – the students
have not studied metallic bonding yet, but will probably
accept alloys.
2. Let them try the non-octet examples by themselves.
At some stage you will need to tell them that they do not
have to obey the octet rule.
3. Develop a cartoon molecule to demonstrate the nature of
covalent bonding and its properties.
© Pearson Education Ltd 2008
This document may have been altered from the original
2
Weekly Plan 7
Homework suggestions
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Questions at the end of the double page spreads
Try dot-and-cross diagrams and shapes of analogous molecules such as PH 3, H2S, etc.
Cross-curriculum links
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Technology – properties of materials
Extension ideas
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Dot-and-cross diagrams for more difficult compounds, e.g. C2H4, NaOH, H2O2 etc.
The shapes of more complicated molecules, e.g. PCl5, C2H4, H2O2 etc.
Find the structure of three simple covalent molecules that contain an odd number of electrons in total.
Draw the structures of other dative covalently-bonded molecules such as Al2Cl6 and NH3BF3.
Potential misconceptions
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Students often think that boiling simple covalent molecules involves breaking the covalent bonds. Covalent bonds are intramolecular whereas boiling breaks
intermolecular forces.
They also think that all molecules obey the octet rule – they will meet examples where the octet rule is not adhered to here.
Notes
The web links referred to here are some that the author has found personally helpful but are not intended to be a comprehensive list, many other
good resources exist.
© Pearson Education Ltd 2008
This document may have been altered from the original
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