Lesson Plan

• Describe the parts of an atom and where they are located.
• Explain how atomic number and mass number are determined.
• Calculate the maximum number of electrons in a given shell using the 2n² rule.
• Compare isotopes based on differing neutron numbers.
• Relate electron‑shell arrangement to the position of elements in the periodic table.

• Projector and screen
• PowerPoint slides with labelled atom diagram
• Printed worksheet (isotope & shell calculations)
• Foam‑ball atom model (nucleus & shells)
• Periodic‑table handouts
• Whiteboard and markers

Begin with a quick “What is an atom?” poll to activate prior knowledge. Show a striking image of a modern atomic model and ask students to guess its parts. Explain that by the end of the lesson they will be able to name each part, calculate shell capacities, and link this to the periodic table.

1. Do‑Now (5'): Students write down everything they know about atoms on a sticky note; share a few responses.
2. Direct Instruction (10'): Present the nucleus, protons, neutrons, and electron shells with the PowerPoint slides.
3. Guided Practice (12'): Work through the 2n² formula together, calculating capacities for K, L, M shells.
4. Interactive Modelling (10'): Students build a simple atom model using foam balls, placing protons, neutrons, and electrons in correct shells.
5. Application (8'): Worksheet activity – identify atomic number, mass number, and isotopes for given elements.
6. Check for Understanding (5'): Quick exit quiz (3 multiple‑choice questions) via Kahoot.

Recap the key parts of the atom and how the 2n² rule determines shell capacity. Students complete an exit ticket stating one way the shell structure influences element placement in the periodic table. Assign homework: complete the worksheet on isotopes and prepare a short paragraph describing the atom of a chosen element.