Lesson Plan

• Describe the three sub‑atomic particles and their key properties.
• Explain isotopic notation and calculate neutron numbers from mass numbers.
• Interpret mass‑spectrometer data to identify isotopic composition.
• Construct electronic configurations using the Aufbau, Pauli exclusion, and Hund rules.
• Predict electron removal or addition when writing configurations for common ions.

• Projector and screen for diagrams and videos.
• Whiteboard and markers.
• Handouts with isotope tables and orbital‑filling order.
• Mass‑spectrometer simulation software or video.
• Periodic‑table posters.
• Worksheets for practice calculations.

Start with a quick poll: Who can name the three particles that make up an atom? Review that protons define the element while neutrons vary to give isotopes. Today we will explore how these particles are visualised, how isotopes are identified with a mass spectrometer, and how electrons are arranged in orbitals. Success will be measured by correctly completing the isotope calculation and writing electronic configurations.

1. Do‑now (5') – Students list sub‑atomic particles, their charges and relative masses on sticky notes.
2. Mini‑lecture (10') – Explain particles, isotopes, and notation with diagrams.
3. Interactive simulation (12') – Use mass‑spectrometer software to generate spectra for carbon and chlorine isotopes; students interpret m/z values.
4. Guided practice (10') – Work through electronic‑configuration examples (H, C, Fe) applying Aufbau, Pauli, and Hund rules.
5. Quick check (5') – Exit ticket: write the configuration for a given ion (e.g., Fe²⁺).

Summarise that atomic number determines element identity, isotopes differ in neutron count, mass spectrometry reveals isotopic composition, and electron configurations follow specific rules. Students submit an exit ticket with one electronic configuration and one isotope calculation. Homework: complete a worksheet on isotope abundances and write configurations for the first twenty elements.