Periodic Table

1. Periodic Table Chemistry 11

2. The Periodic Table • Began with Mendeleev • Sequenced elements based on increasing atomic mass • Additionally, elements with similar properties were grouped together

3. Modern Periodic Table • Instead of using Atomic Mass, the table is organized by Atomic Number • According to Periodic Law • The chemical and physical properties of the elements repeat in a regular, periodic pattern when they are arranged according to their atomic number

4. Read Page 16Practice Problem 6 Page 17

5. Electrons and the Periodic Table • The Noble Gases (Group 18 or VIIIA) are so named because they are very stable • They do not react under most conditions because they are understood to have a full outer shell of electrons • Use the number of electrons in each Noble Gas to determine the number of electrons to fill each electron shell

6. Noble Gas He Ne Ar Kr Xe Rn Uuo Electrons 2 10 18 36 54 86 118 Electrons and the Periodic Table • Valence Electrons • 2 • 8 • 8 • 18 • 18 • 32 • 32

7. Valence Electrons • The number of electrons in the outer shell are known as the Valence Electrons • The number of Valence Electrons an atom has determines, in large part, its chemical properties • Based upon the patterns of Valence Electrons, the Periodic Table can be displayed as seen on page 19

8. Problems • Practice Problems 7 & 8 Page 20 • Section Review 1-7 Pages 20-21