O Levels/IGCSE Chemistry Lesson Plan 11.1

Section	Details
Objective	– Define structural formula and describe its unambiguous nature.- Draw and interpret displayed formulae for simple organic molecules.
Activities	– Starter (5 mins): Show images of ethene, ethanol, and ethyl ethanoate and ask: “How are the atoms arranged in these molecules?”- Main (25 mins): 1. Define structural formula as a representation of the arrangement of atoms in a molecule. 2. Show examples of structural formulae, e.g., CH₂=CH₂, CH₃CH₂OH, CH₃COOCH₃. 3. Introduce displayed formulae, showing all atoms and bonds, and practice drawing simple organic molecules. 4. Discuss the differences between structural and displayed formulae.- Plenary (10 mins): Students complete a worksheet drawing the displayed formulae for given structural formulae.
Resources	Molecular models, whiteboard for drawing formulae, worksheets.
Time	40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary).
Homework	Draw and label the structural and displayed formulae for propene, propanol, and ethanoic acid.
Assessment	Worksheet: Match structural formulae to displayed formulae.
Past Paper Practice	IGCSE Chemistry 0620/41/O/N/21 Q6(a) – Drawing displayed formulae.

Section	Details
Objective	– Write and interpret general formulae of alkanes, alkenes, alcohols, and carboxylic acids.- Explain the general characteristics of a homologous series.
Activities	– Starter (5 mins): Ask: “What do methane, ethene, and ethanol have in common?”- Main (25 mins): 1. Define homologous series and introduce their general characteristics: – Same functional group. – Same general formula. – Differ by a −CH2−-CH_2- unit. – Show trends in physical properties. – Share similar chemical properties. 2. Write general formulae for alkanes (CnH2n+2C_nH_{2n+2}), alkenes (CnH2nC_nH_{2n}), alcohols (CnH2n+1OHC_nH_{2n+1}OH), and carboxylic acids (CnH2n+1COOHC_nH_{2n+1}COOH). 3. Practice deriving molecular formulae using general formulae.- Plenary (10 mins): Students complete a table listing the general formula, functional group, and example compounds for each homologous series.
Resources	Periodic table, worksheets, molecular model kits.
Time	40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary).
Homework	Write molecular formulae for the first three members of alkanes, alkenes, alcohols, and carboxylic acids.
Assessment	Worksheet: Match molecular formulae to their respective homologous series.
Past Paper Practice	IGCSE Chemistry 0620/41/M/J/20 Q6(b) – General formulae and homologous series.

Section	Details
Objective	– Identify functional groups of organic compounds and their role in chemical properties.- Define structural isomers and identify isomers for given molecular formulae.
Activities	– Starter (5 mins): Show examples of ethanol and ethanoic acid and ask: “What makes these molecules behave differently?”- Main (25 mins): 1. Define functional group as the atom or group of atoms responsible for the characteristic reactions of a homologous series. 2. Identify functional groups for alkanes (none), alkenes (C=C), alcohols (OH), and carboxylic acids (COOH). 3. Define structural isomers and show examples using C4H10C_4H_{10} (butane and methylpropane) and C4H8C_4H_8 (but-1-ene and but-2-ene). 4. Practice identifying and drawing isomers for given molecular formulae.- Plenary (10 mins): Students complete a matching exercise linking functional groups to homologous series and practice drawing structural isomers.
Resources	Molecular models, functional group diagrams, worksheets.
Time	40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary).
Homework	Draw all structural isomers for C5H12C_5H_{12} and C3H6C_3H_6, identifying their functional groups.
Assessment	Worksheet: Identify functional groups and structural isomers for given compounds.
Past Paper Practice	IGCSE Chemistry 0620/41/O/N/20 Q6(c) – Functional groups and structural isomerism.

Section	Details
Objective	– Define saturated and unsaturated compounds.- Explain how to identify unsaturated compounds using chemical tests.
Activities	– Starter (5 mins): Show samples of vegetable oil and butter and ask: “Why is oil liquid and butter solid at room temperature?”- Main (25 mins): 1. Define saturated compounds (single C-C bonds) and unsaturated compounds (one or more C=C bonds). 2. Discuss examples: alkanes (saturated), alkenes (unsaturated). 3. Demonstrate the bromine water test: – Unsaturated compounds decolorize bromine water. – Saturated compounds do not react with bromine water.- Plenary (10 mins): Students complete a table classifying given compounds as saturated or unsaturated based on their structure and bromine water test results.
Resources	Bromine water, molecular models, worksheets.
Time	40 minutes total: 5 mins (Starter) + 25 mins (Main) + 10 mins (Plenary).
Homework	Write a short explanation of why alkenes react with bromine water while alkanes do not.
Assessment	Worksheet: Identify compounds as saturated or unsaturated based on their structure and reactions with bromine water.
Past Paper Practice	IGCSE Chemistry 0620/41/M/J/19 Q6(b) – Saturated and unsaturated compounds.

Structural Formula:
- Shows how atoms are arranged in a molecule (e.g., CH3CH2OHCH_3CH_2OH).
Homologous Series:
- Same functional group, general formula, and chemical properties.
- Examples: Alkanes (CnH2n+2C_nH_{2n+2}), Alkenes (CnH2nC_nH_{2n}), Alcohols (CnH2n+1OHC_nH_{2n+1}OH).
Functional Groups:
- Determine chemical properties of compounds (e.g., OH for alcohols, COOH for carboxylic acids).
Saturated vs Unsaturated:
- Saturated: Only single C-C bonds (e.g., alkanes).
- Unsaturated: One or more C=C bonds (e.g., alkenes).

Use molecular models and real-life examples to make abstract concepts tangible.
Encourage hands-on drawing of structural and displayed formulae for better understanding.
Provide ample opportunities for students to practice identifying homologous series, functional groups, and isomers.