1. Differentiating Chemical Reactions from Nuclear Reactions 1

2. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

3. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

4. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

5. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

6. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

7. CHEMICALNUCLEAR Occurs when bonds are broken or formed. Occurs when nuclei emit particles and/or rays. Atoms remained unchanged, though may be rearranged. Atoms often converted into atoms of another element. Involves valence electronsMay involve protons, neutrons or electrons Small energy changesHUGE energy changes Reaction rates affected by temp and pressure Reaction rate NOT normally affected temp and pressure

8. Write a multiple-choice test question for the previous chart.

9. 9 Nuclear Radiation Natural Radioactivity A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.

10. Radioactivity Any process where the nucleus emits particles or energy

11. 11 Unstable nucleus.

12. 12 Radioactive Isotopes A radioactive isotope has an unstable nucleus emits radiation to become more stable can be one or more isotopes of an element is written with a mass number and an atomic number includes the mass number in its name Example: iodine-131

13. 13 Examples of Radioactive Isotopes

14. 14 Learning Check Thallium-201 is used for heart scans to determine cardiac function. A. How many protons are in thallium-201? B. How many neutrons are in thallium-201? C. What is the atomic symbol of thallium-201?

15. 15 Nuclear Radiation Nuclear radiation is the radiation emitted by an unstable atom takes the form of alpha particles, neutrons, beta particles, positrons, or gamma rays A representation of a Geiger-Müller counter

16. 16 Alpha Particle An alpha (  ) particle has a helium nucleus 2 protons and 2 neutrons a mass number of 4 a charge of 2+ a low energy compared to other radiation particles

17. 17 Beta Particle A beta (  ) particle is a high-energy electron has a mass number of 0 has a charge of 1- forms in an unstable nucleus when a neutron changes into a proton and an electron

18. 18 Positron A positron (  + ) has a mass number of 0 has a charge of 1+ forms in an unstable nucleus when a proton changes into a neutron and a positron

19. 19 Gamma (  ) Ray A gamma (  ) ray is high-energy radiation has a mass number of 0 has a charge of 0 is emitted from an unstable nucleus to give a more stable, lower energy nucleus

20. 20 Summary of Common Forms of Nuclear Radiation

21. 21 Learning Check Give the mass number and charge of each type of radiation. 1. alpha particle 2. positron 3. beta particle 4. neutron 5. gamma ray

22. 22 Radiation protection requires paper and clothing for alpha particles a lab coat or gloves for beta particles a lead shield or a thick concrete wall for gamma rays limiting the amount of time spent near a radioactive source increasing the distance from the source Radiation Protection

23. How Far Away? Inverse Square Law Write a multiple choice test question over this topic!

24. 24 Radiation and Shielding Required

25. 25 Radiation Protection Different types of shielding are needed for different radiation particles. Radioactive particles/rays vary greatly in penetrating power.

26. 26 Learning Check Indicate the type of radiation (alpha, beta, and/or gamma) protection for each type of shielding. 1) heavy clothing 2) paper 3) lead 4) lab coat 5) thick concrete A person working with radioisotopes wears protective clothing and gloves and stands behind a shield.

27. 27 Nuclear Radiation Nuclear Equations A radon gas detector is used to determine radon levels in buildings with inadequate ventilation.

28. Radioactive Decay In radioactive decay, a nucleus spontaneously emits radiation a nuclear equation is written for the radioactive nucleus, the new nucleus, and the radiation emitted Radioactive nucleus new nucleus + radiation ( , , ,  + ) 28

29. 29 In a nuclear equation, the type of radiation emitted causes changes in the mass numbers changes in the atomic numbers for the nuclei of the unstable and stable nuclei Nuclear Equations

30. 30 In a balanced nuclear equation, the sum of the atomic numbers for the nuclei of the reactant and the products must be equal Mass Numbers Total = 238 = 238 Total = 92 = 92 Atomic Numbers Balancing Nuclear Equations

31. 31 Guide to Completing a Nuclear Equation

32. 32 Alpha Decay In alpha decay, a radioactive nucleus emits an alpha particle to form a new nucleus that has a mass number 4 less than that of the initial nucleus an atomic number that has decreased by 2 from that of the initial nucleus

33. 33 Example of Writing an Equation for Alpha Decay Write an equation for the alpha decay of STEP 1 Write the incomplete nuclear equation. STEP 2 Determine the missing mass number. 222 = ? + 4 222 – 4 = 218 218 = ? (mass number of new nucleus)

34. 34 Equation for Alpha Decay (continued) STEP 3 Determine the missing atomic number. 86 = ? + 2 86 – 2 = ? 84 = ? (atomic number of new nucleus STEP 4 Determine the symbol of the new nucleus. Symbol of element 84 = Po STEP 5 Complete the nuclear equation.

35. 35 Beta Decay Beta decay occurs when an electron (beta particle) is emitted from the nucleus a neutron in the nucleus breaks down

36. 36 Write an equation for the beta decay of potassium-42. STEP 1 Write the incomplete nuclear equation. STEP 2 Determine the missing mass number. 42 = ? + 0 42  0 = 42 = ? (mass number of new nucleus) STEP 3 Determine the missing atomic number. 19 = ?  1 19 + 1 = ? 20 = ? (atomic number of new nucleus) Writing an Equation for a Beta Emitter

37. 37 STEP 4 Determine the symbol of the new nucleus. Symbol of element 20 = Ca STEP 5 Complete the nuclear equation. Writing an Equation for a Beta Emitter (continued)

38. 38 Write the nuclear equation for the beta decay of Xe-133. Learning Check

39. 39 In positron emission, a proton is converted to a neutron and a positron the mass number of the new nucleus is the same, but the atomic number decreases by 1 Positron Emission

40. 40 Write the nuclear equation for the positron emission by Rb-82. Learning Check

41. 41 In gamma radiation, energy is emitted from an unstable nucleus, indicated by m following the mass number the mass number and the atomic number of the new nucleus are the same Gamma (  ) Radiation

42. 42 Summary of Types of Radiation

43. 43 Producing Radioactive Isotopes Radioactive isotopes are produced when a stable nucleus is converted to a radioactive nucleus by bombarding it with a small particle in a process called transmutation

44. 44 What radioactive isotope is produced when a neutron bombards cobalt-59 and an alpha particle is emitted? Learning Check

45. 45 Recall From Lab: The decay series.

46. 46 Nuclear Radiation Radiation Measurement A radiation technician uses a Geiger Counter to check radiation levels.

47. 47 Radiation Detection A Geiger counter detects beta and gamma radiation uses ions produced by radiation to create an electrical current

48. 48 Radiation Measurement Radiation units of activity include curie (Ci) SI unit = becquerel (Bq) number of atoms that decay in one second 1 Ci = 3.7 x 10 10 disintegrations/s 1 Ci = 3.7 x 10 10 Bq rad (radiation absorbed dose) SI unit = gray(Gy) radiation absorbed by the tissues of the body 1 Gy = 100 rad rem (radiation equivalent) SI unit = sievert (Sv) biological damage caused by different types of radiation = absorbed dose (rad) x factor 1 Sv = 100 rem

49. 49 Units of Radiation Measurement

50. 50 Exposure to Radiation Exposure to radiation occurs from naturally occurring radioisotopes medical and dental procedures air travel, radon, and smoking cigarettes

51. Radiation Sickness 51 Radiation sickness depends on the dose of radiation received at one time is not detected under 25 rem involves a decrease in white blood cells at 100 rem includes nausea and fatigue over 100 rem reduces white-cell count to zero over 300 rem leads to death in 50% of people at 500 rem

52. 52 Nuclear Radiation Half-Life of a Radioisotope The age of the Dead Sea scrolls was determined using carbon-14.

53. 53 Half-Life The half-life of a radioisotope is the time for the radiation level (activity) to decrease (decay) to one-half of its original value.

54. 54 Decay Curve A decay curve shows the decay of radioactive atoms the remaining radioactive sample

55. 55 Half-lives of Some Radioisotopes Half-lives of radioisotopes that are naturally occurring tend to be long used in nuclear medicine tend to be short

56. 56 In one half-life, 40 mg of a radioisotope decays to 20 mg. After two half-lives, 10 mg of radioisotope remain. 40 mg x 1 x 1 = 10 mg 2 2 1 half-life 2 half-lives Initial 40 mg 20 mg 10 mg Half-Life Calculations

57. 57 Examples of Half-Lives

58. 58 Using Half-lives

59. 59 The half-life of iodine-123 is 13 h. How much of a 64-mg sample of I-23 is left after 26 h? 1) 32 mg 2) 16 mg 3) 8 mg Learning Check

60. 60 Nuclear Radiation Medical Applications Using Radioactivity Used by >>1 in 3 admitted to hospital

61. 61 Medical Applications Radioisotopes with short half-lives are used in nuclear medicine because they have the same chemistry in the body as the nonradioactive atoms give off radiation that exposes a photographic plate (scan), giving an image of an organ

62. 62 Using a Scanner to Detect Radiation (a) A scanner is used to detect radiation from a radioisotope that has accumulated in an organ. (b) A scan of the thyroid show the accumulation of radioactive iodine-131 in the thyroid.

63. Radioactive Tracers Technetium-99 6 hr half-life Accumulate in cells with rapid growth (tumors)

64. Radioactive Tracers: Gadolinium-153 Accumulated in bone Osteoporosis

65. Radioisotopes in Nuclear Medicine 65

66. 66 Learning Check Which of the following radioisotopes are most likely to be used in nuclear medicine? 1) K-40 half-life 1.3 x 10 9 years 2) K-42 half-life 12 hours 3) I-131 half-life 8 days Write a test question regarding radioactive tracers used in medicine.

67. 67 Positron Emission Tomography (PET) In positron Emission Tomography (PET), positrons are emitted from positron emitters such as carbon -11, oxygen-15, and fluorine-18 positrons are used to study brain function and metabolism positrons combine with electrons to produce gamma ray that can be detected, giving a three- dimensional image

68. 68 Positron Emission Tomography (PET) These PET scans of the brain show a normal brain on the left and a brain affected by Alzheimer’s disease on the right.

69. 69 Computed Tomography (CT) In computed tomography (CT), 30 000 X-rays are directed at the brain in layers are absorbed at different rates due to differences in densities of body tissues and fluids create three-dimensional images of the brain and any tumors or hemorrhages

70. 70 Computed Tomography (CT) A CT scan shows a brain tumor (yellow) on the right side of the brain.

71. 71 Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI) protons in the presence of a strong magnetic field align with the magnetic field protons release energy when magnetic field is removed protons in different environments emit energies of different frequencies to provide images of soft tissue

72. 72 Magnetic Resonance Imaging (MRI) An MRI scan provides images of the heart and lungs.

73. 73 Nuclear Radiation Nuclear Fission and Fusion

74. 74 In nuclear fission, a large nucleus is bombarded with a small particle the nucleus splits into smaller nuclei and several neutrons large amounts of energy are released Nuclear Fission

75. 75 Nuclear Fission When a neutron bombards U-235, an unstable nucleus of U-236 forms and undergoes fission (splits) smaller nuclei are produced such as Kr-91 and Ba-142 neutrons are released to bombard more U-235 nuclei

76. 76 Nuclear Fission

77. E=mc 2 E  energy m  mass c  speed of light (3.0 x 10 8 m/s) Small mass=large output Mass of proton and neutron in the nucleus is less than the same protons and neutrons separate? Missing mass is the mass defect = to binding energy. Convert mass to energy = equation tells you how much energy

78. Critical Mass Minimum fissionable isotopes needed to provide neutrons to sustain chain reaction

79. 79 Chain Reaction A chain reaction occurs when a critical mass of uranium undergoes fission releasing a large amount of heat and energy that produce an atomic explosion

80. 80 Chain Reaction

81. 81 Learning Check Supply the missing atomic symbol to complete the equation for the following nuclear fission reaction.

82. 82 Nuclear Power Plants In nuclear power plants, fission is used to produce energy control rods in the reactor absorb neutrons to slow the fission process Nuclear power plants supply about 10% of the electricity in the United States.

83. 83 Diagram of a nuclear power plant.

84. Copyright © by McDougal Littell. All rights reserved. 84 Schematic of the reactor core.

85. 85 Nuclear Power Plants

86. 86 Diagram for the tentative plan for deep underground isolation of nuclear waste.

87. Fusion Interior of sun 15 million °C Nuclei combine H ‘s combine to form He

88. 88 Nuclear Fusion Nuclear fusion occurs at extremely high temperatures (100 000 000 °C) combines small nuclei into larger nuclei releases large amounts of energy occurs continuously in the sun and stars

89. 89 Nuclear Fusion

90. 90 Indicate if each of the following is 1) nuclear fissionor 2) nuclear fusion ___ A. a nucleus splits ___ B. large amounts of energy are released ___ C. small nuclei form larger nuclei ___ D. hydrogen nuclei react ___ E. several neutrons are released Classify each as fission or fusion Learning Check

91. Concept Map 91

92. Smoke Detectors Alpha emitters Charged current with smoke Am-241