This chemistry video tutorial focuses on periodic trends such as ionic radius and atomic radius. It provides plenty of examples and explains the fundamental concepts of why some ions are smaller than atoms while others are larger. Here is a list of topics 1. Atomic Radii decreases left to right 2. Effective Nuclear Charge, Atomic Number, and Number of Protons 3. Atomic Radius Increases from top to bottom in the periodic table due to additional energy levels 4. Neutral vs Positively Charged Ion / Cation – Number of Shells or Energy Levels 5. Neutral Parent Atom vs Negatively Charged Ion / Anion – Electron Repulsion & Electron Cloud Expansion 6. General Ionic Radii Trend – Cations are smaller than Anions