Key Concepts Covered

1. Bohr Model of the Atom
- The Bohr model shows electrons orbiting the nucleus in rings called energy levels
- Each energy level can hold a specific maximum number of electrons

2. Electron Configuration
- Electrons fill energy levels starting from the innermost level
- The number of electrons in each level is given on the periodic table
- The outermost energy level contains the valence electrons

3. Valence Electrons
- Valence electrons are in the outermost energy level
- The number of valence electrons determines many chemical properties
- Elements in the same group (column) on the periodic table have the same number of valence electrons

4. Drawing Bohr Diagrams
- Start with the nucleus containing protons and neutrons
- Add rings for each energy level
- Fill rings with correct number of electrons, starting from the innermost level
- The outermost ring shows the valence electrons

5. Using the Periodic Table
- The atomic number gives the number of protons (and electrons in a neutral atom)
- The mass number (rounded atomic mass) gives the total protons and neutrons
- The electron configuration is shown at the bottom of each element's box

Practice
- Students practiced drawing Bohr diagrams for different elements
- Calculated number of protons, neutrons, and electrons
- Identified number of valence electrons for various elements

This lesson helps students understand atomic structure and how electrons are arranged in atoms, which is fundamental for understanding chemical behavior and bonding.