1. Chapter 3 & 24 Nuclear Chemistry

2. Changes in the Nucleus Chemical Reactions – involve electrons & electron cloud in basic reactions Chemical Reactions – involve electrons & electron cloud in basic reactions The nucleus remains stable & unchanged Nuclear Reactions: change the composition of an atom’s nucleus Nuclear Reactions: change the composition of an atom’s nucleus

3. Demo Observe what you see? Observe what you see? What is causing the balloons behavior? What is causing the balloons behavior? Why does that not occur in the nucleus of an atom? Why does that not occur in the nucleus of an atom?

4. Section 3-4 Note Figure 3-27 [p112] Note Figure 3-27 [p112] Black arrows – force of electrical repulsion Black arrows – force of electrical repulsion Blue arrows – strong nuclear force Blue arrows – strong nuclear force Which diagram represents a stable nucleus & a unstable nucleus? Which diagram represents a stable nucleus & a unstable nucleus?

5. Nuclear Stability Note Figure 3-28 [p113] Note Figure 3-28 [p113] Notice the “belt of stability” Notice the “belt of stability” Elements #1-20 (#protons = #neutrons) Elements #1-20 (#protons = #neutrons) Then what happens??? Then what happens??? At what point is no number of neutrons sufficient to “clue” the nucleus together At what point is no number of neutrons sufficient to “clue” the nucleus together All nuclei with atomic numbers greater than 83 are radioactive… those are??? All nuclei with atomic numbers greater than 83 are radioactive… those are???

6. Radioactivity Note p 99… Note p 99… Becquerel (1896) --- discovered the radioactivity of uranium…[note picture] Becquerel (1896) --- discovered the radioactivity of uranium…[note picture] Marie & Pierre Curie isolated two other radioactive elements, Radium & Polonium Marie & Pierre Curie isolated two other radioactive elements, Radium & Polonium Rutherford discovered 3 radioactive particles – Alpha, Beta & Gamma Rutherford discovered 3 radioactive particles – Alpha, Beta & Gamma

7. Types of Radiation [p114] NameIdentity ChargePenetrating Ability AlphaHelium-4 nuclei2+Low, stopped by paper BetaElectrons1-Medium, stopped by heavy clothing GammaHigh energy non- particle radiation NoneHigh, stopped by lead

8. Radioactive Decay When an atom emits one of these kinds of radiation particles, it is undergoing radioactive decay When an atom emits one of these kinds of radiation particles, it is undergoing radioactive decay The original nucleus decomposes, or decays to forma new nucleus and releases radiation in the process. The original nucleus decomposes, or decays to forma new nucleus and releases radiation in the process. Note p115…Alpha decay Note p115…Alpha decay Note p 116… Beta decay Note p 116… Beta decay

9. Types of decay Alpha decay Alpha decay Helium nucleus Helium nucleus No electrons No electrons

11. Alpha Decay p115 222 Ra --------222Rn + 4 alpha 222 Ra --------222Rn + 4 alpha 88 86 2 88 86 2 Nucleus ejects a helium nucleus (alpha particle) & becomes a smaller nucleus

12. Types of decay Beta decay Beta decay An electron An electron In this type of decay a neutron is converted into a proton and the beta particle. In this type of decay a neutron is converted into a proton and the beta particle.

14. Beta Decay p116 131 I 131 Xe + 0 Beta 131 I 131 Xe + 0 Beta 53 54 -1 53 54 -1 Turning a neutron in the nucleus into a proton, which ejects an electron in the process.

15. Types of decay Gamma decay – just energy Gamma decay – just energy

16. Correct & continue work Worksheets 3-4 explore Worksheets 3-4 explore P119 #1-4 P119 #1-4 Balancing Nuclear Equations WS Balancing Nuclear Equations WS

17. The blood of Julius Caesar Is in your hands… Is in your hands… Why? Why? Think back to Lavoisier and the law of conservation of mass Think back to Lavoisier and the law of conservation of mass The carbon, iron, nitrogen, and other elements that made up all ancient things are still here The carbon, iron, nitrogen, and other elements that made up all ancient things are still here Stability Stability

18. Isotopes Defined: Defined: The same atom with a different number of neutrons The same atom with a different number of neutrons Most nuclei are stable Most nuclei are stable Some are not Some are not

19. Americium-241 Half-life = 475 yrs P 780

20. Nuclear Medicine I

21. Radiocarbon Dating Defined Defined Defined Method of using unstable carbon atoms to determine age of ‘things’ Method of using unstable carbon atoms to determine age of ‘things’ Relies on radioactive isotopes Relies on radioactive isotopes Scientists ‘count’ half-lives Scientists ‘count’ half-lives Libby

22. Source of C-14 Source of C-14 11/19 Amount is constant Produced by cosmic rays N-14 converted to C-14 Organic life incorporates C-14 until death

23. Radioisotopes Nucleus changes, atoms decay Nucleus changes, atoms decay Give off radiation Give off radiation Decay is spontaneous Decay is spontaneous Becquerel Becquerel Stored photo paper with uranium, paper was exposed Stored photo paper with uranium, paper was exposed Becquerel

24. Half-Life of radioisotopes Length of time required for half of a given sample of a radioisotope to decay Length of time required for half of a given sample of a radioisotope to decay Note p 779 for list of half-lives & type of decay Note p 779 for list of half-lives & type of decay

25. Half Life Defined: Defined: The time it takes for ½ of a sample of a radioactive element to decay The time it takes for ½ of a sample of a radioactive element to decay Can be short or long Can be short or long Rb-87 = 60 billion years Rb-87 = 60 billion years C-14 = 5730 years C-14 = 5730 years Iodine-129 = 15.7 million years Iodine-129 = 15.7 million years Iodine-131 = 8 days Iodine-131 = 8 days See figure 24-4 p 779 See figure 24-4 p 779

26. Practice 1 (sample p780) The half-life of an isotope of plutonium is 140 days. If the original sample contained 10 g, how much of it will be present after 420 days? The half-life of an isotope of plutonium is 140 days. If the original sample contained 10 g, how much of it will be present after 420 days?

27. Practice 2 (sample p 780) Gold-191 has a half-life of 12.4 hours. What mass of gold-191 will remain after 86.8 hours if you started with 13.50 mg of the pure isotope? Gold-191 has a half-life of 12.4 hours. What mass of gold-191 will remain after 86.8 hours if you started with 13.50 mg of the pure isotope?

28. Finish Work Complete the following and turn in tomorrow --- Complete the following and turn in tomorrow --- P119 #1-4 P119 #1-4 WS 3-4 WS 3-4 Balancing Nuclear Equations WS Balancing Nuclear Equations WS Reading 777-785 p 185 #1-3 Reading 777-785 p 185 #1-3

29. 11/24/15 3-4 RR worksheet 3-4 RR worksheet P 785 #1-3 P 785 #1-3 Due today… Please have nb out with p785 for review and credit! Today… “Hanford” Watch with a particular person in mind… reflect & think as this person Today… “Hanford” Watch with a particular person in mind… reflect & think as this person

30. Fusion / Fission Nuclei & Nuclear Particles can react in a variety of different ways. Nuclei & Nuclear Particles can react in a variety of different ways. Nuclear Fusion: 2 hydrogen nuclei collide to form a helium nucleus, releasing a great amount of energy Nuclear Fusion: 2 hydrogen nuclei collide to form a helium nucleus, releasing a great amount of energy Nuclear Fission: reactions involving the splitting a nucleus. (nuclear reactors produces energy by splitting the nuclei of large atoms, such as Uranium-235) Nuclear Fission: reactions involving the splitting a nucleus. (nuclear reactors produces energy by splitting the nuclei of large atoms, such as Uranium-235)

31. Nuclear Bombardment Method to make a stable nucleus unstable Method to make a stable nucleus unstable Involve the nucleus being hit with particles such as a neutron or an entire nucleus Involve the nucleus being hit with particles such as a neutron or an entire nucleus

33. How do we get Pu? Plutonium build up (Pu – Atomic Number 94) Plutonium build up (Pu – Atomic Number 94) Plutonium build up Plutonium build up Bombardment reactions take place in a particle accelerator Bombardment reactions take place in a particle accelerator Large Hadron Collider, CERN 16.7 miles in circumference

34. Special note… I-129 Found throughout the environment around the world Found throughout the environment around the world Most released from nuclear weapons testing in the 50s and 60s Most released from nuclear weapons testing in the 50s and 60s

35. X X

36. Particle Acceleration Accelerate particles to near the speed of light and impact on another object Accelerate particles to near the speed of light and impact on another object Another atom Another atom Bubble chamber Bubble chamber

37. High Dose X-ray Beware, rather gruesome Beware, rather gruesome Interesting tutorial in x-ray safety here Interesting tutorial in x-ray safety herehere

38. Living Tissue Gamma radiation Gamma radiation Follows straight path through tissue Follows straight path through tissue Strips electrons off of molecules Strips electrons off of molecules Creates ions – hence ‘ionizing radiation’ Creates ions – hence ‘ionizing radiation’ Ions of organic compounds are called free radicals Ions of organic compounds are called free radicals Tear apart molecules and cells Tear apart molecules and cells

39. Tissue effects Effect Threshold Dose Effect Threshold Dose Erythema (skin reddening) 300 – 500 rem Temporary hair loss 300 – 500 rem Permanent hair loss 700 rem Transepidermal injury (skin burns) 1000 rem Erythema (skin reddening) 300 – 500 rem Temporary hair loss 300 – 500 rem Permanent hair loss 700 rem Transepidermal injury (skin burns) 1000 rem Dermal radionecrosis (tissue death) 2000 - 3000 rem Dermal radionecrosis (tissue death) 2000 - 3000 rem

40. Leukemia Most common cancer caused by radiation Most common cancer caused by radiation Marie Curie died of leukemia Marie Curie died of leukemia

41. Somatic Damage Damage only to the organism Damage only to the organism Burns Burns Cataracts Cataracts Cancers Cancers

42. Germ Cell Damage “Genetic” damage “Genetic” damage Affects reproductive organs Affects reproductive organs Lead at the doctor’s office… Lead at the doctor’s office… Leads to birth defects Leads to birth defects Affects all offspring Affects all offspring

43. Dosing One time high dose One time high dose Acute sickness Acute sickness Death Death Long term exposure Long term exposure Cancers Cancers Leukemia Leukemia Regulated by the government Regulated by the government

44. Medical Uses Radioactive tagging Radioactive tagging Bone scans Bone scans Use Tc-99 or I=131 or calcium isotope Use Tc-99 or I=131 or calcium isotope Allows doctors to see what is happening inside the body without surgery Allows doctors to see what is happening inside the body without surgery

48. REVIEW -Types of decay Alpha decay Alpha decay Helium nucleus Helium nucleus No electrons No electrons

49. Alpha Decay

50. Types of decay Beta decay Beta decay An electron An electron In this type of decay a neutron is converted into a proton and the beta particle. In this type of decay a neutron is converted into a proton and the beta particle.

52. Types of decay Gamma decay – just energy Gamma decay – just energy

53. Gamma is everywhere

54. Review the Types Alpha Alpha Not good penetrating power Not good penetrating power Beta Beta Stronger penetrating power Stronger penetrating power Gamma Gamma High penetrating power High penetrating power

55. Note the differences of penetration

56. Penetration characteristics

57. Electromagnetic Spectrum

58. Measuring Radiation SI unit is becquerel – named after Henri Becquerel SI unit is becquerel – named after Henri Becquerel Curie Curie 1 curie of alpha is the 1 curie of alpha is the same as 1 curie of gamma radiation

59. Measuring Radiation

60. More common is the rem More common is the rem Measures amount of energy and sensitivity Measures amount of energy and sensitivity 100 rem will cause the same amount of damage no matter if it is gamma or beta radiation 100 rem will cause the same amount of damage no matter if it is gamma or beta radiation Above 1000 rem = fatal Above 1000 rem = fatal Below 1000 rem = makes one sick Below 1000 rem = makes one sick Below 150 rem = tissue damage Below 150 rem = tissue damage

61. Measuring Radiation Dosimeter Dosimeter Has photographic film in it Has photographic film in it Exposure darkens film Exposure darkens film