Lesson Plan

• Describe the meaning of Z (atomic number), A (mass number), and X (element symbol) in nuclide notation.
• Write correct nuclide notation for a given element using its proton and neutron counts.
• Calculate the number of neutrons (N) from the relationship N = A – Z.
• Identify isotopes of an element and explain why their chemical properties are nearly identical.
• Apply the notation to solve short practice problems.

• Whiteboard and markers
• Projector with slide deck of nuclide examples
• Handout containing a nuclide table and practice questions
• Calculator (optional)
• Set of element cards for a quick matching activity

Begin with a quick visual of a nucleus and ask students what information they think is needed to identify an atom. Recall that they already know protons define the element and neutrons add mass. Explain that today they will master the compact nuclide notation and will be able to read and write it confidently.

1. Do‑Now (5'): Students complete a short worksheet converting word problems into Z, A, X values.
2. Mini‑lecture (10'): Present the notation format, explain subscript/superscript placement, and demonstrate with carbon‑12 and uranium‑235.
3. Guided practice (12'): Work through three examples together, calculating N each time and discussing isotopes.
4. Interactive activity (15'): In pairs, students use element cards to build correct nuclide symbols and check each other.
5. Independent practice (8'): Students answer the five practice questions from the source material.
6. Check for understanding (5'): Quick poll – students write one correct nuclide notation on a sticky note.

Summarise how Z, A, and X combine to give a unique identifier for any atom and revisit the isotope concept. Ask students to write the notation for a randomly chosen element as an exit ticket. For homework, assign a worksheet with additional nuclide‑notation problems and a short reflection on why isotopes share chemical behavior.