1. Ch. 11 – Periodicity: Patterns in Periodic Table Explaining Chemical and Physical Properties

2. Review What Patterns do You Already Know? Atomic number Type of Atoms Electron Configurations Alkali Metals Halogens Noble Gases

3. Review: Atomic Numbers

4. Review: Type of Atoms ? ?

5. Review: Electron Configurations

6. Other Physical and Chemical Patterns Melting Points Boiling Points Reactivity – Type of Bonds – Number of Bonds Solubility Density

7. These Patterns of Properties on the Periodic Table Affect Geology…

8. Patterns Affect Health…

9. Two New Important Patterns That affect all Chemical and Physical Characteristics

10. Patterns in Size of Atoms

11. Patterns in Electron Holding Ability

12. 3 Reasons for Patterns Valence Shell Protons per Shell Shielding

13. 1. Valence Shell Occupied More Valence Shells – Farther from nucleus = atom can be larger This pattern can be seen as you look… – Down a Column (size increases at each new row)

14. 2. Protons in Nucleus per Shell For atoms occupying a given shell (say the second shell… – Lithium has 3 protons (3+) can hold electrons in the second shell “OK” – Neon has 10 protons (10+), and has much more attractive force to hold electrons, can hold electrons in the second shell “STRONGLY” Strong attraction “skrunches” the size of the atom This is called “electron affinity” and the atoms on the right side of the periodic table “skrunch” the size – Across the Row (size “skrunches” as you move to the right from group to group)

15. 3. Shielding When there are many electrons in the inner shells – Interfere with ability of protons to attract electrons – This pattern can be seen as you look Down a Column

16. Practice Which atoms are largest or smallest? Which atoms are least able to hold valence electrons? Consider – Shell – Electron Affinity – Shielding Rank these atoms – Potassium – Fluorine – Carbon

17. Quiz 1.What are the two new patterns on the Periodic Table that you have to learn about? 2.What are the three main reasons for these patterns?