1. Warm Up9-28-15 1. What are valence electrons? 2. How many valence electrons do elements in the alkali and halogen group have? 3. Which of these elements are metal? Al, As, Cl, Li 4. What are the charges of the subatomic particles? Homework Quiz next class Unit 3 Finish review WS Agenda -Notes Unit 3-3 -Lab Conservation of mass -WS Unit 3 Quiz Review

2. SEAP - Science & Engineering Apprenticeship Program  Deadline to apply Oct. 23  Must be 16 or older during the summer   Spend 8 weeks during the summer doing research at the Naval Surface Warfare Center - (behind Norco College)   $3,300 stipend for the 8 weeks  https://seap.asee.org/

3. SEAP - Science & Engineering Apprenticeship Program   Applicant has to write 4 statements including:   Career goals: describe your career goals and in which way this program would help you fulfill those goals.   Academic interests: describe any special interest you may have that would make you a valuable participant. Describe any awards or honors you have received.   Research experience: describe any research experience you may have in relation to this program.   Technical skills: describe any technical skills you may have, related to the science and engineering disciplines.

4. Unit 3-3 Periodic Trends  Atomic radius  Ionization energy  Electronegativity  Electron affinity

5. Periodic Trends  Atomic Radius: The estimated distance from the nucleus to the outer most electrons  Increases down a group  As electrons energy levels are added, the atom becomes larger  Decreases across a period  # protons increases which pulled the v.e. closer to the nucleus

6. Atomic Radius Trend Radius decreases Radius Increases Radius decreases

7. Periodic Trends  Ionization Energy - The energy required to remove one electron from an atom or ion  Decreases down a group  Electrons are farther from the nucleus and easier to remove  Increases across a period

8. Periodic Trends  Electron Affinity - the energy change that occurs when an electron is added to a neutral atom  Decreases down a group  Increases across a period

9. Periodic Trends  Electronegativity - the ability of an atom to attract electrons to itself  Decreases down a group  Increases across a period

10. Check In   Consider the following elements: Ca, Fe, Ga, Br   Largest radius?   Smallest radius?   Highest electronegativity?   Lowest ionization energy level?

11. Trends Summarize

12. Conservation of Mass  Purpose: Find a method to test the law of conservation of mass  Materials: electronic  Materials: electronic scale1 balloon 125 mL flask5 g baking soda 50ml graduated cylinder 15 mL vinegar 1) Weight of baking soda = _______g 2) Weight of compounds and reaction vessel before reaction occurs = ________g 3) Weight of compounds and reaction vessel after they reacted = _________g

13. Assignments  Notes Summary  Unit 3 Quiz review worksheet due next class (answers posted tonight after 7PM on my website)