O Levels/IGCSE Physics Lesson Plan 5.1

Section	Details
Objective	– Describe the structure of an atom as a positively charged nucleus surrounded by negatively charged electrons.– Understand how atoms form positive and negative ions by losing or gaining electrons.
Activities	Starter (5 mins): Show a simple diagram of an atom (e.g., hydrogen) and ask students to label its parts.Main (25 mins): 1. Explain the structure of an atom, emphasizing the nucleus and electron orbits.2. Discuss how atoms gain or lose electrons to form ions and provide real-life examples (e.g., sodium forming Na⁺ or chlorine forming Cl⁻).Plenary (10 mins): Students draw and label a simple diagram of an atom and explain ion formation.
Resources	Atomic structure diagrams, whiteboard for sketches.
Time	40 minutes
Homework	Write an explanation of how a sodium atom becomes a sodium ion, including a diagram.
Assessment	Students describe the structure of an atom and explain ion formation during class discussions.
Past Paper Practice	IGCSE Physics 0625/21/M/J/20 Q4(b).

Section	Details
Objective	– Describe how the alpha-particle scattering experiment supports the nuclear model of the atom.– Understand evidence for a small, dense, positively charged nucleus.
Activities	Starter (5 mins): Ask students why a solid gold sheet doesn’t stop alpha particles completely. Show a diagram of the setup for Rutherford’s experiment.Main (25 mins): 1. Describe the alpha-particle scattering experiment and its key observations (most particles pass through, some deflect).2. Explain the conclusions drawn: (a) Atoms have a small nucleus surrounded by empty space. (b) The nucleus contains most of the atom’s mass. (c) The nucleus is positively charged.Plenary (10 mins): Students summarize the experiment and its conclusions in three points.
Resources	Diagram of Rutherford’s alpha-particle scattering experiment, video animation.
Time	40 minutes
Homework	Write a short note on why Rutherford’s experiment disproved the “plum pudding” model of the atom.
Assessment	Students explain the key findings of the alpha-particle scattering experiment during class discussions.
Past Paper Practice	IGCSE Physics 0625/42/M/J/20 Q5(b).

Section	Details
Objective	– Describe the composition of the nucleus in terms of protons and neutrons.– Define proton number (Z) and nucleon number (A) and calculate the number of neutrons in a nucleus.– Understand relative charges of subatomic particles.
Activities	Starter (5 mins): Show examples of atomic nuclei (e.g., hydrogen, helium) and ask students to guess their composition.Main (25 mins): 1. Explain the composition of the nucleus: protons and neutrons.2. Define proton number (atomic number) Z and nucleon number (mass number) A, and show how to calculate the number of neutrons using Neutrons=A−Z\text{Neutrons} = A – Z.3. Discuss relative charges of protons (+1), neutrons (0), and electrons (-1).Plenary (10 mins): Students calculate the number of neutrons for various nuclei using AA and ZZ.
Resources	Chart of elements showing ZZ and AA, examples of nuclei, whiteboard for calculations.
Time	40 minutes
Homework	Find the number of protons, neutrons, and electrons in carbon-12, carbon-14, and oxygen-16.
Assessment	Students calculate the composition of nuclei during class activities.
Past Paper Practice	IGCSE Physics 0625/22/M/J/20 Q5(a).

Section	Details
Objective	– Define isotopes and explain how elements can have more than one isotope.– Describe nuclear fission and fusion as splitting or joining of nuclei.
Activities	Starter (5 mins): Show examples of isotopes (e.g., carbon-12, carbon-14) and ask students what makes them different.Main (25 mins): 1. Define isotopes as atoms of the same element with different numbers of neutrons.2. Provide examples of isotopes and their uses (e.g., carbon-14 in radiocarbon dating).3. Explain nuclear fission and fusion with diagrams and animations, highlighting mass and energy changes.Plenary (10 mins): Students summarize one use of isotopes and the difference between fission and fusion.
Resources	Diagrams of isotopes, animations of fission and fusion, whiteboard for summaries.
Time	40 minutes
Homework	Write a paragraph comparing nuclear fission and fusion, including examples of where they occur.
Assessment	Students define isotopes and explain nuclear processes during discussions.
Past Paper Practice	IGCSE Physics 0625/32/O/N/20 Q6(a).