Warm-Up February 13, 2013

1. Warm-UpFebruary 13, 2013 • Write down the date and objective. • Objective: SWBAT analyze radioactive decay using nuclear equations by completing Balancing Nuclear Equations. • Complete the following warm-up: • What is the empirical formula of a compound that contains 30.4% nitrogen and 69.6% oxygen by mass? • A compound consists of 25.9% nitrogen and 74.1% oxygen by mass. What is the empirical formula of the compound?

2. Objective & Agenda • Objective: SWBAT analyze radioactive decay using nuclear equations by completing Balancing Nuclear Equations. Agenda • Homework Review • No Excuses Wednesday • Empirical Formula Lab • Nuclear Reactions • Alpha & Beta Decay • Balancing Nuclear Equations • Exit Slip

3. HW 10 Review

4. What if? • Born in Los Angeles to 2 Asian immigrants • Received no athletic scholarships and told he was a “Division – III” player; attended a perennially weak basketball school • Undrafted but signed with an NBA team for the league minimum ($500K!) and then subsequently sent to the Development League 5 separate times • Slept on brother’s couch to save money • Picked up by the Knicks…and then averaged 27.3 points, 8.3 assists, and 2 steals in his first four starts leading the Knicks to 6 straight victories

5. Jeremy Lin • 23-year old Asian-American basketball player who has been blowing up the wires • Dropped 38 points on Kobe last season • Graduated from Harvard with a 3.1/4.0 in Economics • 1,483 points, 487 rebounds, 406 assists and 225 steals. • Wants to be a pastor (Christian) after he finishes hooping

6. Linning? • "[Lin] was scrawny, but don't doubt that a little racial profiling, intentional or otherwise, contributed to his underrecruitment."[120] Diepenbrock stated, "If [Lin] was African American or Caucasian, it might have been a different deal.” • "Maybe I can help break the stereotype," said Lin.[126] "I feel like Asians in general don't get the respect that we may deserve whether it comes to sports, basketball, or whatever it might be."

7. Empirical Formula Lab • New Sheet

8. Nuclear Reactions vs. Ordinary Chemical Reactions • Regular chemical reactions involve only the outer electrons of atoms. In a chemical reaction, elements do not change from one to another. 2H2 + O2 2H2O • Nuclear reactions involve the atomic nucleus. • When an atomic nucleus changes, it is very probable that the products will be different elements than the reactants.

9. Nuclear Reactions • Many nuclei are radioactive. • This means they are unstable and will decay by emitting a particle, transforming the nucleus into another nucleus, or into a lower energy state. • A chain of decays takes place until a stable nucleus is reached.

10. When an atom loses or gains protons, it turns into another elementThis process is called RADIOACTIVE DECAY

11. Atoms experience radioactive decay because they are UNSTABLE - they have too many or not enough neutrons

12. Nuclear Symbols Alpha particle,  Beta particle, an electron,  Neutron

13. Energy of Particles • While all particles produced by the decay of an atomic nucleus have the energy to penetrate substances, some particles have much more energy than others.

14. NOTES • 2 Types of Radioactive Decay • Alpha decay (when an atom emits alpha particles, 2 protons and 2 neutrons) • Beta decay (when an atom emits beta particles, a neutron splits into a proton and an electron…and the electron is kicked out)

15. NOTES Alpha Particles • alpha particles = helium nuclei • Symbol: or α • Mass: 4 grams • Charge: +2

16. How do we write that out? Alpha Decay Example: When 226Ra loses an alpha particle, what atom does it become? • Law of Conservation of Mass: So the atomic mass on left side must EQUAL atomic mass on right side. Atomic Mass = 222 + 4 Atomic Number = 86 + 2 NOTES 226 Ra 88

17. Practice! • When 274Hs loses an alpha particle, what atom will it turn into?

18. Partner Practice! • When 238 U loses an alpha particle, what atom will it turn into?

19. NOTES Beta Particles • Beta particles = high speed electrons • Symbol: • Mass: 0 • Charge: -1

20. NOTES Practice When 210Bi loses a beta particle, what atom does it become?

21. Another Practice When 218Po loses a beta particle, what atom does it become? Decay type: ______________

22. Partner Practice! • When 14C loses a beta particle, what atom will it turn into?

23. Balancing Nuclear Equations

24. Fission vs. Fusion • Fission: heavy nuclei are split into lighter nuclei. Fission reactions are relatively easy to control but produce radioactive wastes. • Fusion: light nuclei are combined to form heavier nuclei. Fusion reactions are difficult to initiate and control but produce little radioactive wastes.

25. Fission vs. Fusion • In nuclear fusion, small nuclei are combined to form a larger nucleus – this process releases a very large amount of energy, and is the main source of energy in the sun. In nuclear fission, large nuclei break apart to form smaller ones, releasing a large amount of energy. Fission is used in nuclear power plants to generate energy.

26. Fission

27. Fusion

28. Modern Uses • Using your textbook or the internet, research uses of nuclear energy, including, but not limited to: electricity, carbon-14 dating and radioisotopes for medical uses. • Write at least two paragraphs (5 sentences each) describing the modern uses including pros and cons.

29. Exit SlipFebruary 13, 2013 1. Given the reaction: 22688Ra  22286Rn + X What is represented by X? 2. Given the reaction: 2411Na  2412Mg + 0-1e This reaction is best described as what? 3. According to the equation: X  20882Pb + 42He What is the nucleus correctly represented by X?