2. Valence Electrons and Reactivity Ms. Millimet August 28, 2014

3. Entrance Procedure Come in silently Sit down at seat Get science study buddy binder out Write down homework Write down objective for day in notebook Prepare for video for Do First

4. Answer the following questions based on the video What is the same and what is different about each element used in the demonstration? (Think about atomic structure) What part of the atomic structure determines that all of these metals will react with water?

5. Video Questions What is the same and what is different about each element used in the demonstration? Same: In the same group Soft, shiny metals React violently with water. All have the same # of valence electrons (and are metals) Difference: energy levels, atomic mass, atomic number, number of protons, number of neutrons, number of electrons What part of the atomic structure determines that all of these metals will react with water? the number of valence electrons

6. Objective Determine the number of valence electrons for any atom based on its location on the periodic table. Explain how the number of valence electrons is related to the chemical reactivity of an element, especially the lack of reactivity demonstrated by the noble gases.

7. Arrangement of Periodic Table Organization on Periodic Table What it means An element’s period on the PT - Equal to the number of energy levels (rings) in element’s atoms. - All elements in same energy level have same number of energy levels An element’s group on the PT - Equal to the number of valence electrons for all elements in group - Elements in same group have similar properties An element’s atomic number - Equal to the number of protons - Determines element’s identity

8. Valence electrons These electrons

9. Valence electrons Valence electrons are the outermost electrons in an atom. They are the electrons that sit furthest from an atom’s nucleus.

10. How many valence electrons? Show me on your fingers after 15 seconds of Table Talk.

11. How many valence electrons does one atom of Nitrogen (N) have?

12. Valence electrons Valence electrons determine how reactive an element is. All atoms want to have a full outer energy level, with 8 electrons If an atom has just 1 or 7 valence electrons, it is very reactive. If an atom has 2 or 6 valence electrons, it is somewhat reactive If an atom has 3, 4, or 5 valence electrons, it is not very reactive If an atom has an outer energy level full of electrons, it does not react. These elements are called noble gases in group 18/ 8A

13. Now let’s connect valence electrons to the Periodic Table Elements in the same group share the same number of valence electrons. Group 1 = 1 valence electron Group 2 = 2 valence electrons 2 valence electrons = group #___? Go ahead and double check on your Periodic Table! Go ahead and double check on your Periodic Table!

14. Predict how many valence electrons! How many valence electrons does…. Hydrogen have? Oxygen have? Neon have? Group 1 = 1 valence electron Group 16 (6A) =6 valence electron Group 18 (8A) = 8 valence electron

15. Let’s reflect… What happens to protons as you move from LEFT  RIGHT and TOP  BOTTOM on the Periodic Table?

16. Let’s reflect… What do all the elements within a GROUP have in common? HINT: look at the electrons!

17. Let’s reflect… What do all the elements within a PERIOD have in common? HINT: look at the electrons again!

18. Reactivity Questions How many valence electrons does argon have? How many valence electrons does chlorine have? What is more reactive? Chlorine or Argon?

19. Reactivity Questions How many valence electrons does Sodium (Na) have? How many valence electrons does Neon have? Which is more reactive Neon or Sodium?