Lesson Plan

• Describe the meaning of proton number (Z) and nucleon number (A) in nuclear notation.
• Explain the relationship N = A − Z and how to determine the neutron number.
• Apply the formula to calculate neutrons for given isotopes.
• Identify and correct common misconceptions about Z, A, and N.
• Interpret nuclear symbols to extract Z and A values.

• Projector or interactive whiteboard
• PowerPoint/slide deck on nuclear notation
• Printed worksheet with practice questions
• Set of isotope cards or models
• Calculator (optional)
• Whiteboard and markers

Begin with a quick visual of a nucleus diagram and ask students what the symbols Z, A, and N might represent. Review that protons determine the element and nucleons include both protons and neutrons. Explain that today they will learn to calculate neutron numbers and will demonstrate mastery through worked examples and practice problems. Success will be measured by correctly completing the worksheet and explaining the relationship N = A − Z.

1. Do‑now (5'): Students answer a quick question on the periodic table to recall atomic numbers.
2. Mini‑lecture (10'): Present definitions of Z, A, N and the equation N = A − Z with a schematic diagram.
3. Guided examples (10'): Work through carbon‑12 and calcium‑40 calculations while students follow on their worksheets.
4. Collaborative practice (12'): Pairs solve three practice questions; teacher circulates to check understanding.
5. Misconception check (8'): Discuss common errors using clicker responses or show of hands.
6. Exit ticket (5'): Students write the neutron number for a given isotope on a sticky note for quick assessment.

Summarize that Z identifies the element, A counts total nucleons, and N is found by subtracting Z from A. Remind students to use this relationship in future isotope problems. For homework, assign five additional isotope calculations to reinforce the skill. Collect exit tickets as a quick check of understanding.