A brief power point presentation designed to help introduce high school chemistry students to reading the periodic table and extracting information such as the number of valence electrons an element has, etc.

3. Mendeleev’s Periodic Table Zumdahl, Steven S. Chemical Principles 5 th Ed. Houghton Mifflin; 2005.

4. The Modern Periodic Table www.collegeboard.com

7. Electron Dot Diagrams Shells are represented by circles and electrons are represented by dots. Example: Helium Nucleus: 2 protons, 2 neutrons 2 electrons in 1 st shell 2p 2n

8. More Examples Carbon 6 protons, 6 neutrons, 6 electrons 1 st Shell: 2 electrons 2 nd Shell: 4 electrons Sodium 11 protons, 12 neutrons, 11 electrons 1 st Shell: 2 electrons 2 nd Shell: 8 electrons 3 rd Shell: 1 electron 11p 12n 6p 6n

9. Valence Electrons The electrons in the outermost electron shell. Helium 2 Valence Electrons Carbon 4 Valence Electrons Sodium 1 Valence Electron 2p 2n 6p 6n 11p 12n

13. Periodic Table IA IIA IIIA IVA VA VIA VIIA VIIIA

16. Example Sodium Atom 1 Valence Electron Charge = 11 + (-11) =0 11p 12n 11p 12n Sodium Ion 8 Valence Electrons Charge = 11 + (-10) = 1

18. Anion Example Fluorine Atom 7 Valence Electrons Charge = 9 + (-9) =0 Fluorine Ion 8 Valence Electrons Charge = 9 + (-10) =-1 9p 10n 9p 10n

19. Example

20. Another Cation Magnesium Atom 2 Valence Electrons Charge = 12 + (-12) =0 Magnesium Ion 8 Valence Electrons Charge = 12 + (-10) =2 12p 12n 12p 12n

21. Another Anion Oxygen Atom 6 Valence Electrons Charge = 8 + (-8) =0 Oxygen Ion 8 Valence Electrons Charge = 8 + (-10) =-2 8p 8n 8p 8n

22. Average Atomic Mass 6 C 12.011 Atomic number Average atomic mass (amu) Why an average atomic mass?

24. Isotope Notation

25. What is the average atomic mass of carbon? trace 14 Carbon-14 1.1 13 Carbon-13 98.9 12 Carbon-12 % Abundance Atomic Mass Isotope