This chemistry video tutorial explains the concepts of periodic trends such as first ionization energy, electron affinity, atomic radius, and ionic radii, electronegativity and metallic character. It contains plenty of examples and practice problems. Here is a list of topics: 1. Periodic Trends - Atomic Size 2. Atomic Radii - Effective Nuclear Charging - Adding Protons to Increase The Charge of the Nucleus 3. Inner Core Electrons vs Outer Valence Electrons 4. Atomic Radius Increases from left to right 5. Atomic Radii Increases from top to bottom on the periodic table 6. Shielding Effect and Electron Repulsion 7. Coulomb's Law Equation / Formula - Relationship Between Electrostatic Force, Distance, and Charge - like charges repel and opposite charges attract. 8. Ionic Radii Trend - Cations vs Anions 9. Positively Charged Ions are Smaller Than Parent Neutral Atom 10. Negatively Charged Ions are Larger Than Parent Atom 11. How to calculate the number of electrons in an atom or ion 12. Principal quantum number and number of shells - atomic size 13. How to rank the elements in order of increasing atomic radii 14. how to rank isoelectronic ions in decreasing order of atomic / ionic size 15. isoelectronic species - same electron configuration 16. Metallic Character Trend - Metals vs Nonmetals 17. Electronegativity Trend - The ability of an atom to attract an electron to itself - increases toward fluorine 18. Electronegative Nonmetals vs Electropositive Metals 19. First Ionization Energy Trend - Increases left to right and bottom to top across a group 20. Ionization Energy - Energy required to remove an electron from a gaseous atom 21. First Ionization Energy vs Second Ionization Energy 22. Jump in Ionization Energy - Number of Valence Electrons 23. Ionization Energy Exceptions - Paired vs Unpaired Electrons in 2s and 2p orbitals 24. Electron Affinity Trend - The Energy change associated with the addition of an electron to a gaseous atom 25. Exothermic vs Endothermic Electron Affinity Processes 26. Half Filled vs Empty S and p orbitals 27.