AS and A Level CHEMISTRY ASample 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 1AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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1 1.1.1 (a) experimental design, including to solve problems set in a practical context1.1.1 (b) identification of variables that must be controlled, where appropriate1.1.1 (c) evaluation that an experimental method is appropriate to meet the expected outcomes

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

© OCR 2015 2AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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2 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 charge2.1.1 (a) isotopes as atoms of the same element with different numbers of neutrons and different masses2.1.1 (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

Multiple choice quiz on ions, isotopes, and electron shellsNice 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: 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

© OCR 2015 3AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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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–, SO4

2–, OH–, NH4+,

Zn2+ and Ag+

* 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: SO4

2–, NO3–, CO3

2–, 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 4AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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4 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

Chemistry and cookingLearner 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.

© OCR 2015 5AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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5 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

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)

Apply the mole concept to substancesThis 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

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?

* 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: 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.

© OCR 2015 6AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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6 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 masses2.1.3 (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!

* 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.

© OCR 2015 7AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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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 results1.1.1 (c) evaluation that an experimental method is appropriate to meet the expected outcomes1.1.4 (c) the limitations in experimental procedures

Determination of the formula of hydrated magnesium sulfateExperiment 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 8AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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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 sulfateExperiment 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 concentration2.1.3 (f) the ideal gas equation: pV = nRT2.1.3 (i) the techniques and procedures required during experiments requiring the measurement of mass, volumes of solutions and gas volumesPAG 1 Moles determination

Working through molar relationshipsThe ‘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)

The volume of 1 mole of hydrogen gasThis 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 -

* 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: (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.

© OCR 2015 9AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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Delivery guide (PDF, 1MB)Activity: The volume of 1 mole of hydrogen gas

The Ideal Gas EquationThese 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 calculatorThis 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

Mole day activitiesThis 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.

© OCR 2015 10AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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12 2.1.3 (h) calculations to determine:(i) the percentage yield of a reaction or related quantities(ii) the atom economy of a reaction

The difference between percentage yield and atom economyVideo.Atom economy and percentage yield - Delivery guide (PDF, 1MB)Activity: The difference between percentage yield and atom economy

Calculating percentage yieldThis 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 yieldThis 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

* 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.

© OCR 2015 11AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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13 2.1.3 (j) the benefits for sustainability of developing chemical processes with a high atom economy

Green chemistry, atom economy and sustainable developmentAn excellent resource that links yield, atom economy and sustainability into one well-structured 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

IbuprofenThis 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

* 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.

© OCR 2015 12AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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14 1.1.2 (c) presenting observations and data in an appropriate format1.1.3 (a) processing, analysing and interpreting qualitative and quantitative experimental results1.1.3 (b) use of appropriate mathematical skills for analysis of quantitative data1.1.3 (c) appropriate use of significant figures

* Demonstrate the reaction of hydrogen and oxygen (http://www.nuffieldfoundation.org/practical-chemistry/reaction-hydrogen-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.

15 2.1.4 (b) qualitative explanation of strong and weak acids in terms of relative dissociations2.1.4 (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 solution2.1.4 (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

Acid, bases and pHThis 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 videoShort 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.

© OCR 2015 13AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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Neutralisation role playTeacher 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 saltThis 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 14AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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16 2.1.4 (d) the techniques and procedures used when preparing a standard solution of required concentration and carrying out acid–base titrations2.1.4 (e) structured and non-structured titration calculations, based on experimental results of familiar and non-familiar acids and basesPAG 2: Acid–base titration

Gridlocks concentrationsCould 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 1Answer sheet: Concentration of solutions 1

Neutralisation of indigestion tabletsTitration 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 stepsStep-by-step guide to titration calculations.Acids and redox - Delivery guide (PDF, 1MB)

Titration calculation gridGrid method for titration calculations.Acids and redox - Delivery guide (PDF, 1MB)

* 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.

© OCR 2015 15AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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17 2.1.5 (a) rules for assigning and calculating oxidation number for atoms in elements, compounds and ions2.1.5 (b) writing formulae using oxidation numbers2.1.5 (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

Oxidation and reduction number lineA 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)

Roman numeral quizzesVarious 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

* Introduce topic of redox; check prior learning.* Introduce topic of oxidation number. Points to cover: 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 16AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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18 2.1.5 (d) oxidation and reduction in terms of:(i) electron transfer(ii) changes in oxidation number2.1.5 (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.

Gridlocks oxidation numbersUse to consolidate oxidation number rules, before or whilst students calculate oxidation states.Acids and redox - Delivery guide (PDF, 1MB)Worksheet: Oxidation numbersAnswer sheet: Oxidation numbers

Reducing agentsSeries of videos covering redox reactions.Acids and redox - Delivery guide (PDF, 1MB)Videos: Reducing agents

Redox equations videoVideo which uses the recommended method for writing redox equations from half-equations.Acids and redox - Delivery guide (PDF, 1MB)

Video: Redox equations

* Refer back to definitions of oxidation and reduction used at GCSE: 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.

19 2.2.1 (a) the number of electrons that can fill the first four shells2.2.1 (b) atomic orbitals, including:(i) as a region around the nucleus that can hold up to two electrons, with opposite spins

Electron configuration activitiesA range of activities about electronic configuration.Atoms and equations - Delivery guide (PDF, 1MB)

* 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-

© OCR 2015 17AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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(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-shells2.2.1 (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 pairing2.2.1 (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

Definitions in ChemistryAlthough 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

Chemistry vignettesThis 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

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 sub-shells and writing electron configurations. Set the worksheets from the same set of links as homework.

© OCR 2015 18AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

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(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' diagrams2.2.2 (b) explanation of the solid structures of giant ionic lattices, resulting from oppositely charged ions strongly attracted in all directions e.g. NaCl2.2.2 (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

RSC starter for ten pack on bondingRange 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 studentsAn 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 bondingThis 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 (CO3

2–, SO42–, NO3

–, HCO3–,

PO43– & OH–) including correct nomenclature

* Explain ion formation in terms of electron transfer and using ‘dot-and-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.

© OCR 2015 19AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

Notes

Card sortFour 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 20AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

Notes

21 2.2.2 (d) covalent bond as the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms2.2.2 (e) construction of ‘dot-and-cross’ diagrams of molecules and ions to describe:(i) single covalent bonding(ii) multiple covalent bonding(iii) dative covalent (coordinate) bonding2.2.2 (f) use of the term average bond enthalpy as a measurement of covalent bond strength

Covalent bondingThis 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

RSC starter for ten pack on bondingRange 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 studentsAn interactive quiz on ionic and covalent bonding.Bonding - Delivery guide (PDF, 1MB)Activity: Plenary: Quick 5-minute plenary to check students’ basic understanding

* 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.

© OCR 2015 21AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

Notes

22 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 electrons2.2.2 (h) electron pair repulsion to explain the following shapes of molecules and ions: linear, non-linear, trigonal planar, pyramidal, tetrahedral and octahedral

Explore molecule shapes by building molecules in 3DOnline 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

An interactive tutorial and quizThis 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 activityDrag 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

* 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–, SO4

2–, CO32–.

* Review learning using the drag and drop activity and quiz, depending on ability.

© OCR 2015 22AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

Notes

23 2.2.2 (i) electronegativity as the ability of an atom to attract the bonding electrons in a covalent bond; interpretation of Pauling electronegativity values2.2.2 (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

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.

© OCR 2015 23AS and A Level Chemistry A

Lesson Specification statements Teaching activities (from scheme of work builder)

Notes

24 2.2.2 (k) intermolecular forces based on permanent dipole–dipole interactions and induced dipole–dipole interactions

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: 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 24AS and A Level Chemistry A