Practical Skills Handbook

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Practical Skills Handbook
AS and A Level CHEMISTRY A
Sample application of scheme of work builder
The following table is a sample of a scheme of work that can be created using the OCR scheme of work builder for AS and A Level Chemistry A
(H032/H432). This sample has been created by a teacher. It includes plans for the first 24 lessons of teaching the AS or A Level, based on an
assumption of 4 lessons per week.
This sample can be seen as an exemplar of how the scheme of work builder can be used to construct lessons, combining suggested activities with
the teacher’s own added notes. This scheme of work represents just one approach to the first weeks of teaching the Chemistry A specification. You
may wish to approach teaching of the content very differently; this is absolutely fine – the approach presented here should not be seen as prescribed
by OCR, or recommended as suitable for all centres. However, you are welcome to use this sample scheme of work directly, or to adapt it to your
own needs, if you feel it will be helpful.
At the time of writing (August 2015) the scheme of work builder does not export in Microsoft Word format. This file has been created by copying the
output from the scheme of work builder into a Microsoft Word template, although it can also be printed directly from the website once it has been
created. Planned updates to the functionality of the scheme of work builder include in first instance the ability to import and export schemes of work to
transfer them to other machines and share them with colleagues, and to save schemes of work online to retrieve them at a later date. The ability to
export in Microsoft Word will be added thereafter.
We recommend that teachers in due course use the facility to store and update schemes of work online, and to return regularly to the scheme of work
builder. The scheme of work builder will be continually updated with additional suggested activities, providing a richer range of support as time
progresses.
© OCR 2015
AS and A Level Chemistry A
1
Lesson Specification statements
1
1.1.1 (a) experimental design,
including to solve problems set in
a practical context
1.1.1 (b) identification of variables
that must be controlled, where
appropriate
1.1.1 (c) evaluation that an
experimental method is
appropriate to meet the expected
outcomes
© OCR 2015
AS and A Level Chemistry A
Teaching activities (from scheme of
work builder)
Notes
Discuss (and learners make notes)
1.1.1 (a)
* Equipment List - include:

accuracy(+/–) for each apparatus

reasons why each apparatus is suitable

possible/potential errors list for each apparatus (e.g. parallax,
'plane' surface, proximity to window, 'time lag' to performing a
function (e.g. risk of 'escaping gas' during time lag))
* Exemplar thought or actual expt: measuring rate of reaction using
HCl(aq), marble chips, gas syringe et al. Test learner responses using
exemplar expt.
1.1.1 (b)
* Recap on meaning of: independent variable, dependent variable,
controlled variables (learners think about why first two are 'singular'
and last one is 'plural')
* Test learners’ ideas on exemplar expt.
1.1.1(c)
* Come up with (via Q&A/e.g.’s) definitions of: accuracy, precision
2
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
2
Multiple choice quiz on ions, isotopes,
and electron shells
Nice activity to review prior learning and
also practice multiple choice questions.
Atoms and equations - Delivery guide
(PDF, 1MB)
Activity: Multiple choice quiz on Ions,
Isotopes, and Electron Shells
* Activities to review prior learning:
2.1.1 (b) atomic structure in terms
of the numbers of protons,
neutrons and electrons for atoms
and ions, given the atomic
number, mass number and any
ionic charge
2.1.1 (a) isotopes as atoms of the
same element with different
numbers of neutrons and different
masses
2.1.1 (c) explanation of the terms
relative isotopic mass (mass
compared with 1/12th mass of
carbon-12) and relative atomic
mass (weighted mean mass
compared with 1/12th mass of
carbon-12), based on the mass of
a 12C atom, the standard for
atomic masses
© OCR 2015
AS and A Level Chemistry A

multiple choice quiz

have learners draw an 'empty' atom structure (nucleus and
surrounding shells: He 1 shell, Li 2 shells, Na 3 shells), then name
the 3 subatomic particles and draw them into their diagrams

ask learners to define atomic number and mass number, then
explain why those terms are so-called.
* Ask learners to discuss "what makes atoms different from one
another"; introduce idea of isotopes.
* Learners draw oxygen ('filled in' nucleus and shells) - mass 18, 17
and 16 and hydrogen - mass 1, 2 and 3; then explain why they are the
same atom followed by recalling the general term given to them
* Learners discuss and explain why an atom is neutral (thinking about
relative charges, positive, negative & neutral), then define an ion
(prompted by “what happens when an atom gains or loses an
electron"; the terms 'anion' and 'cation' may then be introduced)
* Learners read through relevant pages of textbook, write definitions of
relative isotopic mass and relative atomic mass, answer related
questions
3
Lesson Specification statements
3
2.1.2 (a) the writing of formulae of
ionic compounds from ionic
charges, including:
(i) prediction of ionic charge from
the position of an element in the
periodic table
(ii) recall of the names and
formulae for the following ions:
NO3–, CO32–, SO42–, OH–, NH4+,
Zn2+ and Ag+
Teaching activities (from scheme of
work builder)
Notes
* Rules for simple & compound ions ( to be 'displayed’ in some way):

ions are charged particles; charges for ions in Groups 1,2,13–18
of the periodic table are related to group position

metals (and hydrogen) - lose outer electron(s) and become
positive ions (number of electrons they lose determines the
number of their charge - e.g. lose 2 electrons ... becomes 2+ ion;
e.g Group 2 metal ion Mg2+ has 10 electrons)

non-metals - gain electron(s) and become negative ions (number
of electrons they gain determines the number of their charge –
e.g. gain 1 electron … becomes 1– ion; e.g. Group 17 non-metal
ion F– has 10 electrons)

compound ions – 2 or more elements joined together with an
overall charge
* Ions list to learn

compound ions: SO42–, NO3–, CO32–, OH–, NH4+; also introduce
PO43–, MnO4–, Cr2O72–, HCO3–
 d-block ions: Ag+, Zn2+
Naming ionic compounds

binary compounds - consist of 2 elements (metal/non-metal):
metal name stays the same/non-metal has 'suffix' IDE (e.g.
sodium chlorIDE)

compound ions with 2 different atoms – one of which is oxygen –
have name ending in ATE (e.g. sodium carbonATE consists of
sodium, carbon and oxygen); exception: NaOH = sodium
hydroxide.
* Learners use the rules above to write the formulae of: sodium
chloride, sodium oxide, sodium sulfate, sodium nitrate (remember
charges must balance overall).
* Set related questions in textbook.
© OCR 2015
AS and A Level Chemistry A
4
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
4
Chemistry and cooking
Learner resource 1.1 in the Delivery guide
is a light hearted starter to encourage
students to understand the value of the
equation in formulating their understanding
of a reaction.
Atoms and equations - Delivery guide
(PDF, 1MB)
* Learners should explain that equations are expressions showing
quantities that are 'equal to one another’. Use ‘Chemistry and cooking’
activity to focus on the importance of equations.
* Ask learners to write the correct formulae for the following: fluorine,
sulfur, oxygen, argon, phosphorus, nitrogen, calcium, zinc, boron,
aluminium. Then extend to writing formulae of compounds as
molecules/formula units, e.g. carbon monoxide (CO), sodium sulfate
(Na2SO4) and for the following: aluminium sulfate, ammonia,
hydrochloric acid, nitric acid, sulfuric acid, water, sodium hydroxide,
carbon dioxide, methane, ethene
* Learners should understand what state symbols are and represent:
(g), (l), (aq), (s).
* Show learners that a balanced equation has the same number of
reactant atoms as product atoms. Learners should appreciate that
when making the number of atoms the same on both sides of a
reaction equation, the element or molecular formula may not be
changed, however the numbers of each product/reactant may be
changed.
* Set relevant questions in textbook.
2.1.2 (b) construction of balanced
chemical equations (including
ionic equations), including state
symbols, for reactions studied
and for unfamiliar reactions given
appropriate information
© OCR 2015
AS and A Level Chemistry A
5
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
5
How many atoms in my signature?
This short activity allows learners to be
introduced to amount of substance, mole
and the Avogadro constant using a
problem-solving approach.
Activity: How many atoms in my signature –
Activity – Instructions (PDF, 209KB)
* Suggested video resources can be set as prior homework to
introduce topic. Many learners will have been introduced to amount of
substance at GCSE.
* Introduce key terms: molar mass, Avogadro constant, amount of
substance (as a 'chemical quantity'), and the 3 equations involving
amount of substance:
2.1.3 (a) explanation and use of
the terms:
(i) amount of substance
(ii) mole (symbol ‘mol’), as the
unit for amount of substance
(iii) the Avogadro
constant, NA (the number of
particles per mole,6.02 ×
1023 mol–1)
(iv) molar mass (mass per mole,
units g mol–1)
(v) molar gas volume (gas volume
per mole, units dm3 mol–1)
2.1.3 (e) calculations, using
amount of substance in mol,
involving
(i) mass
(ii) gas volume
(iii) solution volume and
concentration
Apply the mole concept to substances
This is part of a whole series of videos to
support IB Chemistry but the context is
relevant to almost any chemistry course.
This video introduces the Avogadro
constant and demonstrates the reason for
units of mol–1.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Video: Apply the mole concept to
substances

amount = actual mass (in g) /molar mass (in g mol–1)

amount = concentration (in mol dm –3) × volume (in dm–3)

for a gas at room temperature and pressure: amount = actual
volume/molar volume (24.0 dm3).
* 1 mol of a substance has a mass that is the 'RAM in GRAMs'
(relative atomic mass in g) (e.g. 1 mol of carbon, C, has a mass of 12
g, 1 mol of elemental nitrogen, N, has a mass of 14 g).
* Use the acquired knowledge to calculate quantities in respect of the
above statements, e.g. using ‘How many atoms in my signature’
activity.
* Set relevant questions in textbook.
How big is a mole?
This TEDEd Lesson covers the concept of
the mole in chemistry. This cartoon
introduces the Avogadro constant and the
mole in an entertaining and engaging way.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: How big is a mole?
© OCR 2015
AS and A Level Chemistry A
6
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
6
Carbonate rocks!
This is a similar experiment to the provided
OCR magnesium sulfate activity but with a
different way of interpreting group results
graphically. The experiment is essentially
the well-established practical for
determination of the empirical formula of
magnesium oxide.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: Carbonate rocks!
* Introduce definitions of empirical and molecular formulae, and
introduce and discuss differences between relative molecular mass
and relative formula mass. Opportunity to review differences between
simple molecular and ionic compounds.
* Have learners read through relevant worked examples and answer
relevant questions in the textbook.
* Set homework to read through the practical activity ‘Carbonate
rocks!’ and think about the procedure.
2.1.3 (b) use of the terms:
(i) empirical formula (the simplest
whole number ratio of atoms of
each element present in a
compound)
(ii) molecular formula (the number
and type of atoms of each
element in a molecule)
2.1.1 (e) use of the terms relative
molecular mass, Mr, and relative
formula mass and their
calculation from relative atomic
masses
2.1.3 (c) calculations of empirical
and molecular formulae, from
composition by mass or
percentage compositions by
mass and relative molecular
mass
© OCR 2015
AS and A Level Chemistry A
7
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
7
2.1.3 (b) use of the terms:
(i) empirical formula (the simplest
whole number ratio of atoms of
each element present in a
compound)
(ii) molecular formula (the number
and type of atoms of each
element in a molecule)
2.1.3 (c) calculations of empirical
and molecular formulae, from
composition by mass or
percentage compositions by
mass and relative molecular
mass
Carbonate rocks!
This is a similar experiment to the provided
OCR magnesium sulfate activity but with a
different way of interpreting group results
graphically. The experiment is essentially
the well-established practical for
determination of the empirical formula of
magnesium oxide.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: Carbonate rocks!
Complete 'Carbonate rocks' practical activity. This activity will also
support the practical specification statements 1.1.1(a), 1.1.2(a),
1.1.2(c), 1.1.3(a), 1.1.4(a), 1.2.1(a), 1.2.1(d), 1.2.1(e), 1.2.1(f),
1.2.1(h), 1.2.1(i), 1.2.2(a).
8
2.1.3 (d) the terms anhydrous,
hydrated and water of
crystallisation and calculation of
the formula of a hydrated salt
from given percentage
composition, mass composition or
based on experimental results
1.1.1 (c) evaluation that an
experimental method is
appropriate to meet the expected
outcomes
1.1.4 (c) the limitations in
experimental procedures
Determination of the formula of hydrated
magnesium sulfate
Experiment on the determination of the
formula of hydrated magnesium sulfate.
Determination of the formula of hydrated
magnesium sulfate activity - Teacher
instructions (PDF, 182KB)
Determination of the formula of hydrated
magnesium sulfate - Activity (DOC, 335KB)
Determination of the formula of hydrated
magnesium sulfate - Spreadsheet (XLS,
290KB)
* Have learners read the relevant pages in the textbook and write
down descriptions of the key terms.
* Discuss practical procedures for determining water of crystallisation,
including assumptions inherent in the procedure (that all the water will
have been lost and that no further decomposition has taken place).
Read through the procedure for the practical activity ‘Determination of
the fomula of hydrated magnesium sulfate’.
* Set relevant questions in the textbook.
© OCR 2015
AS and A Level Chemistry A
8
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
9
2.1.3 (d) the terms anhydrous,
hydrated and water of
crystallisation and calculation of
the formula of a hydrated salt
from given percentage
composition, mass composition or
based on experimental results
Determination of the formula of hydrated
magnesium sulfate
Experiment on the determination of the
formula of hydrated magnesium sulfate.
Determination of the formula of hydrated
magnesium sulfate activity - Teacher
instructions (PDF, 182KB)
Determination of the formula of hydrated
magnesium sulfate - Activity (DOC, 335KB)
Determination of the formula of hydrated
magnesium sulfate - Spreadsheet (XLS,
290KB)
Complete ‘Determination of the formula of hydrated magnesium
sulfate’ practical activity. This activity will also support the practical
specification statements 1.1.2(a), 1.1.3(a), 1.1.3(b), 1.1.3(d), 1.2.1(c),
1.2.1(d), 1.2.1(g), 1.2.2(a)
10
2.1.3 (e) calculations, using
amount of substance in mol,
involving:
(i) mass
(ii) gas volume
(iii) solution volume and
concentration
2.1.3 (f) the ideal gas
equation: pV = nRT
2.1.3 (i) the techniques and
procedures required during
experiments requiring the
measurement of mass, volumes
of solutions and gas volumes
PAG 1 Moles determination
Working through molar relationships
The ‘Moles of atoms’ and ‘Moles of
molecules’ worksheets allow students to
develop an understanding of the
relationships between amount of
substance, mole, Avogadro constant and
molar mass before any mathematical
equations have been introduced.
Amount of substance and the mole Delivery guide (PDF, 1MB)
* Set worksheets ‘Moles of atoms’ and ‘Moles of molecules’ from the
Delivery guide prior to the lesson. Check that learners recall the
amount of substance equations with respect to solutions and gases:
© OCR 2015
AS and A Level Chemistry A

(solutions) amount = concentration (in mol dm –3) x volume (in dm3)

(gases) amount = actual volume/24.0 dm3 (volume of 1 mol of any
gas at room temperature and pressure)
* Complete practical work to determine volume of 1 mol hydrogen gas.
Use results to discuss ideal gas theory.
* Set results calculations and relevant questions from textbook as
homework.
The volume of 1 mole of hydrogen gas
This is an interesting approach that links
together amount of substance with mass,
gas volumes and stoichiometry. This would
complement well parts (e) and (f) of this
section of the specification.
Amount of substance and the mole -
9
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
Delivery guide (PDF, 1MB)
Activity: The volume of 1 mole of hydrogen
gas
The Ideal Gas Equation
These videos from the Khan academy
could be useful for students who need
support or as flip learning activity.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: The Ideal Gas Equation
Ideal Gas calculator
This link takes you to a website which
allows students to input values and
calculate using the Ideal Gas Equation. It
could be a good starting point and an option
to support students in becoming familiar
with the equation.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: Ideal Gas calculator
11
2.1.3 (e) calculations, using
amount of substance in mol,
involving:
(i) mass
(ii) gas volume
(iii) solution volume and
concentration
© OCR 2015
AS and A Level Chemistry A
Mole day activities
This link has a number of activities that
could be used to complement the teaching
of the mole.
Amount of substance and the mole Delivery guide (PDF, 1MB)
Activity: Mole day activities
* Review content from previous lessons. Mole day activities could be
used for support where required.
10
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
12
The difference between percentage yield
and atom economy
Video.
Atom economy and percentage yield Delivery guide (PDF, 1MB)
Activity: The difference between percentage
yield and atom economy
* Explain percentage yield and atom economy, and use the video to
introduce the difference between the two.
* Use worksheets to familiarise learners with percentage yield
calculations.
* Set relevant questions from the textbook.
2.1.3 (h) calculations to
determine:
(i) the percentage yield of a
reaction or related quantities
(ii) the atom economy of a
reaction
Calculating percentage yield
This is a worksheet with answers that would
help students reinforce the calculations
required for percentage yield.
Atom economy and percentage yield Delivery guide (PDF, 1MB)
Activity: Calculating percentage yield
Calculating percentage yield
This is another example of a resource that
could be used to calculate percentage yield.
It provides a step-by-step demonstration of
the calculation.
Atom economy and percentage yield Delivery guide (PDF, 1MB)
Activity: Calculating Percentage yield
© OCR 2015
AS and A Level Chemistry A
11
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
13
Green chemistry, atom economy and
sustainable development
An excellent resource that links yield, atom
economy and sustainability into one wellstructured worksheet. It provides
descriptions and questions relating to each
concept.
Atom economy and percentage yield Delivery guide (PDF, 1MB)
Activity: Green chemistry, atom economy
and sustainable development
* Check understanding of terms ‘percentage yield’ and ‘atom
economy’.
* Ask learners to explain sustainability (as a practice towards
answering a 6-mark question), using examples from either the 'Green
Chemistry’ worksheet or the textbook.
* Work through 'Green Chemistry' worksheet and relevant questions
from the textbook.
2.1.3 (j) the benefits for
sustainability of developing
chemical processes with a high
atom economy
Ibuprofen
This is a structured worksheet which
incorporates percentage yield and atom
economy based around the synthesis of
ibuprofen. It will need to be differentiated
according to ability of the students – parts
could be taken away or added, it could also
be used as a stretch and challenge activity.
Atom economy and percentage yield Delivery guide (PDF, 1MB)
Activity: Ibuprofen
© OCR 2015
AS and A Level Chemistry A
12
Lesson Specification statements
14
1.1.2 (c) presenting observations
and data in an appropriate format
1.1.3 (a) processing, analysing
and interpreting qualitative and
quantitative experimental results
1.1.3 (b) use of appropriate
mathematical skills for analysis of
quantitative data
1.1.3 (c) appropriate use of
significant figures
15
2.1.4 (b) qualitative explanation of
strong and weak acids in terms of
relative dissociations
2.1.4 (a) the formulae of the
common acids (HCl, H2SO4,
HNO3 and CH3COOH) and the
common alkalis (NaOH, KOH and
NH3) and explanation that acids
release H+ ions in aqueous
solution and alkalis release OH–
ions in aqueous solution
2.1.4 (c) neutralisation as the
reaction of:
(i) H+ and OH– to form H2O
(ii) acids with bases, including
carbonates, metal oxides and
alkalis (water-soluble bases), to
form salts, including full equations
© OCR 2015
AS and A Level Chemistry A
Teaching activities (from scheme of
work builder)
Notes
* Demonstrate the reaction of hydrogen and oxygen
(http://www.nuffieldfoundation.org/practical-chemistry/reactionhydrogen-and-oxygen-reacting-masses) as an opportunity to review
topics covered in the preceding lessons, and focus on practical skills
relating to presentation and processing of data.
Acid, bases and pH
This short video summarise the
neutralisation reaction and pH. This covers
the KS3 and KS4 knowledge as well as
setting it into a context and applications of
the science.
Acids and redox - Delivery guide(PDF,1MB)
Video: Acids, bases and pH
Distinguishing between weak and strong
acids and bases video
Short video, in the format of a computer
game, explaining relative dissociation of
weak and strong acids and bases.
Acids and redox - Delivery guide(PDF,1MB)
Video: Distinguishing between weak and
strong acids and bases
* Learners to view ‘Acids, bases and pH’ video prior to lesson.
* The ‘Acids, bases and salts’ presentation from
http://www.knockhardy.org.uk/ppoints.htm can be used to present this
topic. Focus on

understanding what an acid is (including ionic equations)

distinguishing between weak and strong acids (the video can
support this)

distinguishing between a base and an alkali (including ionic
equations).
* Cover the formulae and nomenclature of several common acids,
bases and alkalis; cover those in the specification and other examples
e.g. H3PO4, HBr.
* Use the principle of dissociation to explain the varying strength of
acids contain multiple hydrogens (e.g. H2SO4 and H3PO4).
* Explain (including equations and relevant states) the neutralisation of
acids with bases (metal oxides, metal hydroxides and metal
carbonates). The role play activity can provide a quick introduction
and reminder of the basics. Consolidate using ‘Name that salt’.
* Set relevant questions from the textbook.
13
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
Neutralisation role play
Teacher Resource 1 in the Delivery guide is
a quick activity allows you to assess
learners’ knowledge of neutralisation and
pH and gives them an opportunity to move
around and generate discussions.
Acids and redox - Delivery guide(PDF,1MB)
Name that salt
This presentation can be used by learners
to review the products of neutralisation
reactions or to consolidate understanding of
salts.
Acids and redox – presentation(PPTX,2MB)
© OCR 2015
AS and A Level Chemistry A
14
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
16
Gridlocks concentrations
Could be used to review concentration
calculations before starting carrying out
titrations and subsequent titration
calculations.
Acids and redox - Delivery guide(PDF,1MB)
Worksheet: Concentration of solutions 1
Answer sheet: Concentration of solutions 1
* Adapt ‘Neutralisation of indigestion tablets’ activity to cover A-Level
appropriate technique for titration, and to include making up standard
solution to cover all requirements for PAG2.
* Introduce activity, pointing out the reasons for using titrations (e.g.
high level of accuracy). Discuss uncertainties for each piece of
apparatus involved.
* Provide calculation steps and calculation grid resources to support
calculations. Set as homework if not completed in class, along with
relevant questions from textbook and planning question from practical
activity.
2.1.4 (d) the techniques and
procedures used when preparing
a standard solution of required
concentration and carrying out
acid–base titrations
2.1.4 (e) structured and nonstructured titration calculations,
based on experimental results of
familiar and non-familiar acids
and bases
PAG 2: Acid–base titration
Neutralisation of indigestion tablets
Titration practical where the concentration
of alkali in an indigestion tablet is found by
titrating against hydrochloric acid.
Acids and redox - Delivery guide(PDF,1MB)
Activity: Neutralisation of indigestion tablets
Titration calculation steps
Step-by-step guide to titration calculations.
Acids and redox - Delivery guide (PDF,
1MB)
Titration calculation grid
Grid method for titration calculations.
Acids and redox - Delivery guide (PDF,
1MB)
© OCR 2015
AS and A Level Chemistry A
15
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
17
Oxidation and reduction number line
A PowerPoint slide to be used as part of a
lesson in defining reduction and oxidation in
terms of number of electrons lost/gained
and change in oxidation number.
Acids and redox - Delivery guide (PDF,
1MB)
* Introduce topic of redox; check prior learning.
* Introduce topic of oxidation number. Points to cover:
2.1.5 (a) rules for assigning and
calculating oxidation number for
atoms in elements, compounds
and ions
2.1.5 (b) writing formulae using
oxidation numbers
2.1.5 (c) use of a Roman numeral
to indicate the magnitude of the
oxidation number when an
element may have
compounds/ions with different
oxidation numbers
Roman numeral quizzes
Various roman numerals quizzes for
students to practise their knowledge of
roman numerals. Can be completed as
homework or as part of a lesson by using
computers for each student to individually
access it or mini-whiteboards with the
quizzes projected from the screen.
Acids and redox - Delivery guide (PDF,
1MB)
Activity: Roman numeral quizzes

the rules for assigning oxidation numbers and the signs (+ or –)
that prefix the oxidation number (except oxidation number zero 0,
which has no sign)

the simple rules regarding ions; for elements in the s- and p-block
these are linked to the group they are in; the oxidation number is
associated with the charge of the ion (e,g. calcium, Ca, is in Group
2 [forms a 2+ ion], so oxidation number is +2; fluorine, F, is in
Group 17 [forms a 1– ion], so oxidation number is
–1)

the oxidation number rules for non-metals in combination: O: –2;
H: +1; F: –1
* Above rules can be used to determine oxidation number of other
elements in a compound. E.g.

NaOCl: Na = +1; O = –2; therefore Cl must be +1 as overall
oxidation number is 0.
* Learn about ‘special cases’:

H in metal hydrides is the H– ion and so has oxidation number –1
(e.g. NaH)

O in peroxides has oxidation number –1 (H2O2)
 O bonded to F has oxidation number +2 (F2O)
* Practise using Roman numerals in formulae to indicate oxidation
number. Quizzes available as a reminder of Roman numerals if
necessary.
© OCR 2015
AS and A Level Chemistry A
16
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
18
Gridlocks oxidation numbers
Use to consolidate oxidation number rules,
before or whilst students calculate oxidation
states.
Acids and redox - Delivery guide (PDF,
1MB)
Worksheet: Oxidation numbers
Answer sheet: Oxidation numbers
* Refer back to definitions of oxidation and reduction used at GCSE:
2.1.5 (d) oxidation and reduction
in terms of:
(i) electron transfer
(ii) changes in oxidation number
2.1.5 (e) redox reactions of
metals with acids to form salts,
including full equations (see also
2.1.4 c)
2.1.5 (f) interpretation of redox
equations in (e), and unfamiliar
redox reactions, to make
predictions in terms of oxidation
numbers and electron loss/gain.
Reducing agents
Series of videos covering redox reactions.
Acids and redox - Delivery guide (PDF,
1MB)
Videos: Reducing agents
Redox equations video
Video which uses the recommended
method for writing redox equations from
half-equations.
Acids and redox - Delivery guide (PDF,
1MB)
19
2.2.1 (a) the number of electrons
that can fill the first four shells
2.2.1 (b) atomic orbitals,
including:
(i) as a region around the nucleus
that can hold up to two electrons,
© OCR 2015
AS and A Level Chemistry A
Video: Redox equations
Electron configuration activities
A range of activities about electronic
configuration.
Atoms and equations - Delivery guide
(PDF, 1MB)

gain/loss of oxygen
 transfer of electrons.
The former definition is not used as A Level as it only applies in cases
involving oxygen. Linking back to the previous lesson on oxidation
number shows that a new definition for oxidation and reduction can
now be added in terms of
 changes in oxidation number.
* Explain redox reactions: 1) in terms of the statements above, 2)
using simple chemical equations, 3) using terms oxidised and reduced
and identifying relevant species within the reaction process. The
reducing agents videos can be used here.
* Show how reactions of acids with metals exemplify redox reactions.
Include: 1) balanced equation with states, 2) oxidation numbers for
species that are oxidised and reduced, 3) identify (name & explain
why) species are oxidised or reduced
* Introduce the idea of constructing equations for redox reactions (note
candidates are only required to construct equations for metals with
acids at AS); set Redox equations video as homework.
* Set relevant questions from the textbook.
* Prior to lesson, set homework to assess learners are able to recall
and write the electron configurations at the level of shells of the first 20
atoms (e.g. Na 2,8,1). Review if necessary.
* Check understanding of electrons shells in terms of energy levels.
Annotate/update descriptions, introducing the principal quantum
number (n) and the idea that number of electrons in a shell = 2n2.
* Introduce the idea of atomic orbitals and the shapes of s- and p-
17
Lesson Specification statements
with opposite spins
(ii) the shapes of s- and p-orbitals
(iii) the number of orbitals making
up s-, p- and d-sub-shells, and
the number of electrons that can
fill s-, p- and d-sub-shells
2.2.1 (c) filling of orbitals:
(i) for the first three shells and the
4s and 4p orbitals in order of
increasing energy
(ii) for orbitals with the same
energy, occupation singly before
pairing
2.2.1 (d) deduction of the electron
configurations of:
(i) atoms, given the atomic
number, up to Z = 36
(ii) ions, given the atomic number
and ionic charge, limited to s- and
p-blocks up to Z = 36
© OCR 2015
AS and A Level Chemistry A
Teaching activities (from scheme of
work builder)
Notes
Definitions in Chemistry
Although not designed as an activity
specifically directed at gifted and talented
students, this activity is ideal for those
students who find the work on electronic
structure straightforward and do not require
as much consolidation time. The activity is
very open ended and encourages students
to examine how commonly used chemical
words are defined and to identify any flaws
or misleading terminology within these
definitions.
Atoms and equations - Delivery guide
(PDF, 1MB)
Activity: Definitions in Chemistry: Royal
Society of Chemistry
orbitals.
* Have learners complete a table detailing for the first 4 shells

sub-shells present

number of orbitals

number of electrons in each sub-shell (and consequently in each
shell).
* Use the Powerpoint presentation linked to under ‘Electron
configuration activities’ to introduce the key points of filling of subshells and writing electron configurations. Set the worksheets from the
same set of links as homework.
Chemistry vignettes
This is a series of screencasts which will
help to satisfy the curiosity of students who
want deeper explanations for the principles
of electronic orbital theory. In particular the
sections on 'Quantisation of Energy Levels'
and 'The Shroedinger Atom' provide more
detail on the wave-particle duality of
electrons and on the links between the
observed evidence (atomic absorption and
emission spectra) and the move towards a
more quantum mechanical view of
electrons in atoms.
Atoms and equations - Delivery guide
18
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
(PDF, 1MB)
Activity: Chemistry vignettes – Advanced
Physical Chemistry: Royal Society of
Chemistry
20
2.2.2 (a) ionic bonding as
electrostatic attraction between
positive and negative ions, and
the construction of 'dot-and-cross'
diagrams
2.2.2 (b) explanation of the solid
structures of giant ionic lattices,
resulting from oppositely charged
ions strongly attracted in all
directions e.g. NaCl
2.2.2 (c) explanation of the effect
of structure and bonding on the
physical properties of ionic
compounds, including melting
and boiling points, solubility and
electrical conductivity in solid,
liquid and aqueous states
© OCR 2015
AS and A Level Chemistry A
RSC starter for ten pack on bonding
Range of activities from RSC.
Bonding - Delivery guide (PDF, 1MB)
Activity: Starter: RSC’s ’Starter for Ten’
pack on bonding
Quick 5 minutes plenary to check basic
understanding of students
An interactive quiz on ionic and covalent
bonding.
Bonding - Delivery guide (PDF, 1MB)
Activity: Plenary: Quick 5-minute plenary to
check students’ basic understanding
Plenary - RSC misconceptions: Spot the
bonding
This resource is designed to provide
strategies for dealing with some of the
misconceptions that students have in the
form of ready-to-use classroom resources.
Bonding - Delivery guide (PDF, 1MB)
Activity: Plenary: RSC misconceptions Spot the bonding
* Set the scene by giving examples of important ionic compounds in
everyday use.
* Check that learners are able to

recall the terms cation and anion and give 4 examples of each

recall the 6 main polyatomic anions (CO32–, SO42–, NO3–, HCO3–,
PO43– & OH–) including correct nomenclature
* Explain ion formation in terms of electron transfer and using ‘dotand-cross’ diagrams. Focus on significance of electrostatic attraction
in ionic bonding.
* Have learners complete ‘dot-and-cross’ diagrams to describe the
formation of 4 ionic compounds, e.g. worksheet on ionic bonding from
the RSC starter for 10 pack.
* Describe the structure of ionic compounds and use this to explain
properties: melting and boiling points, solubility, electrical conductivity.
* Set relevant questions from the textbook and/or from linked
resources.
19
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
Card sort
Four types of bonding structures, metallic,
giant ionic, giant covalent, simple covalent
and pictures, descriptions, properties and
example elements/compounds to arrange
under the headings.
Bonding - Delivery guide (PDF, 1MB)
Activity: Plenary: A card sort activity.
© OCR 2015
AS and A Level Chemistry A
20
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
21
Covalent bonding
This activity seeks to develop an
understanding of covalent bonding in terms
of energetic stability rather than full shells.
(An alternative or complementary activity on
ionic bonding may be found on the same
website.)
Atoms and equations - Delivery guide
(PDF, 1MB)
Activity: Covalent bonding
* Explain covalent bonding focusing on electrostatic attraction
between the shared pair of electrons and the nuclei; introduce
examples in textbook. Covalent bonding involves overlap of orbitals
and the attraction is localised (compare to ionic bonding). Have
learners complete the Covalent bonding worksheet to support this.
* Have learners draw the displayed formula of 4 covalent molecules
(including shared pairs and lone pairs of electrons), e.g. from the RSC
starter for 10 pack.
* Show how number of covalent bonds is related to number of
electrons in outer shell. Bonding atoms often achieve noble gas
electron configuration, but not always (e.g. BF3).
* Explain how expansion of the octet is linked to elements from Period
3 onwards as shells can contain more than 8 electrons.
* Have learners draw ‘dot-and-cross’ diagrams for: SF2, SF4, SF6,
BCl3, PF3, PF5, ClF, ClF3, ClF5 and ClF7.
* Use displayed formulae and ‘dot-and-cross’ diagrams of O2, CO2, N2
and HCN to describe multiple covalent bonds (double & triple bonds).
* Use a diagram showing the formation of the ammonium ion to
describe dative covalent bonding.
* Introduce average bond enthalpy as a measure of covalent bond
strength, e.g. pointing out higher enthalpies of multiple vs single
covalent bonds.
* Set relevant questions from the textbook and/or from linked
resources.
2.2.2 (d) covalent bond as the
strong electrostatic attraction
between a shared pair of
electrons and the nuclei of the
bonded atoms
2.2.2 (e) construction of ‘dot-andcross’ diagrams of molecules and
ions to describe:
(i) single covalent bonding
(ii) multiple covalent bonding
(iii) dative covalent (coordinate)
bonding
2.2.2 (f) use of the term average
bond enthalpy as a measurement
of covalent bond strength
RSC starter for ten pack on bonding
Range of activities from RSC.
Bonding - Delivery guide (PDF, 1MB)
Activity: Starter: RSC’s ’Starter for Ten’
pack on bonding
Quick 5 minutes plenary to check basic
understanding of students
An interactive quiz on ionic and covalent
bonding.
Bonding - Delivery guide (PDF, 1MB)
Activity: Plenary: Quick 5-minute plenary to
check students’ basic understanding
© OCR 2015
AS and A Level Chemistry A
21
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
22
Explore molecule shapes by building
molecules in 3D
Online model - students can find out by
adding single, double or triple bonds and
lone pairs to the central atom. Then,
compare the model to real molecules.
Bonding - Delivery guide (PDF, 1MB)
Activity: Main: Explore molecule shapes by
building molecules in 3D
* Explain electron-pair repulsion theory; cover correct notation and
theory of depicting shapes of molecules in three dimensions.
* Use the model to allow learners to explore molecular shapes, and
finding out the effect of adding different types of bonds and lone pairs.
This could be used to allow learners to ‘discover’ the greater repulsion
of lone pairs.
* Have learners draw, name the shapes and label the angles of a
range of molecules covering all shapes referred to in the specification,
and extending to polyatomic ions: NH4+, NO3–, SO42–, CO32–.
* Review learning using the drag and drop activity and quiz,
depending on ability.
2.2.2 (g) the shapes of, and bond
angles in, molecules and ions
with up to six electron pairs
(including lone pairs) surrounding
the central atom as predicted by
electron pair repulsion, including
the relative repulsive strengths of
bonded pairs and lone pairs of
electrons
2.2.2 (h) electron pair repulsion to
explain the following shapes of
molecules and ions: linear, nonlinear, trigonal planar, pyramidal,
tetrahedral and octahedral
An interactive tutorial and quiz
This computer course is designed to teach
the user the electron pair repulsion rules.
Once the user is familiar with the rules a set
of worked examples are available to show
how they are applied to unfamiliar
molecules.
Bonding - Delivery guide (PDF, 1MB)
Activity: Main or plenary: An interactive
tutorial and quiz
Drag and drop activity
Drag and drop activity of shapes and bond
angles can alternatively be laminated as
cards.
Bonding - Delivery guide (PDF, 1MB)
Activity: Main or plenary: Drag and drop
activity
© OCR 2015
AS and A Level Chemistry A
22
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
23
When is a molecule polar?
Students change the electronegativity of
atoms in a molecule to see how it affects
polarity. See how the molecule behaves in
an electric field. Change the bond angle to
see how shape affects polarity. See how it
works for real molecules in 3D.
Bonding - Delivery guide (PDF, 1MB)
Activity: When is a molecule polar?
Learners should:
* Introduce the principle of electronegativity and how uneven bonded
electron pair sharing leads to bond polarity.
* Use the online model to demonstrate how difference in
electronegativity influences the magnitude and direction of the dipole.
Use this to explain Pauling electronegativity values, and introduce the
+/– notation.
* Ask learners to explain why HCl is a polar molecule.
* Review electronegativity; ask learners to identify most and least
electronegative elements in the periodic table.
* Explain how molecular shape / orientation of bonds and bond
polarity determine whether a molecule is polar overall (CO2 and H2O
as examples).
* Review understanding (also of shapes of molecules) using other
examples.
* Set related questions from textbook.
2.2.2 (i) electronegativity as the
ability of an atom to attract the
bonding electrons in a covalent
bond; interpretation of Pauling
electronegativity values
2.2.2 (j) explanation of:
(i) a polar bond and permanent
dipole within molecules
containing covalently-bonded
atoms with different
electronegativities
(ii) a polar molecule and overall
dipole in terms of permanent
dipole(s) and molecular shape
© OCR 2015
AS and A Level Chemistry A
23
Lesson Specification statements
Teaching activities (from scheme of
work builder)
Notes
24
When is a molecule polar?
Students change the electronegativity of
atoms in a molecule to see how it affects
polarity. See how the molecule behaves in
an electric field. Change the bond angle to
see how shape affects polarity. See how it
works for real molecules in 3D.
Bonding - Delivery guide (PDF, 1MB)
Activity: When is a molecule polar?
* Review understanding of electronegativity and polarity from previous
lesson. Move on to description of attraction between polar molecules:
permanent dipole–dipole interactions.
* Point out that non-polar molecules/atoms also interact. This is shown
by the fact that substances with non-polar molecules/atoms can
become liquid/solid – e.g. CO2, methane. These interactions arise due
to induced dipole–dipole interactions.
* Be mindful of terminology:
2.2.2 (k) intermolecular forces
based on permanent dipole–
dipole interactions and induced
dipole–dipole interactions

induced dipole–dipole interactions = London forces

van der Waals’ forces may refer to all dipole–dipole interactions,
and should not be used to refer specifically to induced dipole–
dipole interactions.
* Strength of induced dipole–dipole interactions is related to the
number of electrons in a molecule/atom.
* Have learners compare enthalpies of covalent bonds and
intermolecular forces. Covalent bonds are much stronger.
* Compare properties of simple molecular substances which have
permanent dipole–dipole interactions (e.g. HCl) with substances which
have only induced dipole–dipole interactions (e.g. F2, CO2, H2).
© OCR 2015
AS and A Level Chemistry A
24

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