1. Intro to Nuclear Chemistry
PowerPoint basics from Mrs. Coyle and other Internet Sources

2. Learning Objectives
TLW understand the basic process of nuclear chemistry (TEKS 12)
TLW be able to describe alpha, beta, and gamma radiation (TEKS 12.A)
TLW describe radioactive decay process in terms of balanced nuclear equations (TEKS 12.B)
TLW compare fission and fusion reactions (TEKS 12.C)

3. Anticipatory Exercise
Background Radiation – What’s YOUR Exposure?
Flinn Scientific ChemTopicTM Labs – Book 18, page 2

4. How does a nuclear reactor work?

5. How does a small mass contained in this bomb cause……
Nuclear Bomb of 1945 known as “fat man”

6. …this huge nuclear explosion?

7. Is there radon in your basement?

8. Nuclear Notation

9. Practice Using Nuclear Notation
How would you write the following elements using nuclear notation? H C Co U

10. Nucleons Protons and Neutrons
The nucleons are bound together by the strong force.

11. Atoms of a given element with:
Isotopes
Atoms of a given element with:
same #protons
but
different # neutrons

12. H H H

13. Isotopes of Carbon

14. Radioactive Isotopes
Isotopes of certain unstable elements that spontaneously emit particles and energy from the nucleus.
Henri Beckerel 1896 accidentally observed radioactivity of uranium salts that were fogging photographic film.
His associates were Marie and Pierre Curie.

15. Marie Curie: 1867 - 1934, in Poland as Maria Sklodowska
Lived in France
1898 discovered the elements polonium and radium.

16. Marie Curie a Pioneer of Radioactivity
Winner of 1903 Nobel Prize for Physics with Henri Becquerel and her husband, Pierre Curie (1859 – 1906)
Winner of the sole 1911 Nobel Prize for Chemistry
Sadly, she and Pierre died of radiation poisoning

17. General Nuclear Equations
Handout of Graphic Organizer on General Nuclear Equations

18. 3 Main Types of Radioactive Decay
Alpha a
Beta b
Gamma g

19. Alpha Decay Emission of alpha particles a : helium nuclei
two protons and two neutrons
charge +2e 
can travel a few inches through air
can be stopped by a sheet of paper, clothing.

20. Alpha Decay
Uranium Thorium alpha particle

21. Alpha Decay

22. Beta Decay
Beta particles b: electrons ejected from the nucleus when neutrons decay
( no  p+ +b- )
Beta particles have the same charge and mass as "normal" electrons.

23. Beta Decay
Beta particles b: electrons ejected from the nucleus when neutrons decay
no  p+ +b-
Beta particles have the same charge and mass as "normal" electrons.
Can be stopped by aluminum foil or a block of wood.

24. Beta Decay

25. Beta Decay
Thorium Protactinium beta particle

26. Gamma Decay
Gamma radiation g : electromagnetic energy that is released. 
Gamma rays are electromagnetic waves.
They have no mass.
Gamma radiation has no charge.
Most Penetrating, can be stopped by 1 m thick concrete or a several cm thick sheet of lead.

27. Examples of Radioactive Decay
Alpha Decay
Po  Pb + He
Beta Decay p n e
n  p e
C  N e
Gamma Decay
Ni  Ni g
(excited nucleus)

29. Which is more penetrating & potentially more harmful? Why?

30. Second Graphic Organizer
Nuclear Decay Organizer (pdf) - link

33. Balancing Nuclear Equations
Part II
Balancing Nuclear Equations

34. Balancing Nuclear Reactions
In the reactants (starting materials – on the left side of an equation) and products (final products – on the right side of an equation) – Law of Conservation of Mass
Atomic numbers must balance
and
Mass numbers must balance
Use a particle or isotope to fill in the missing protons and neutrons

35. Nuclear Reactions Alpha emission
Note that mass number (A) goes down by 4 and atomic number (Z) goes down by 2.
Nucleons (nuclear particles… protons and neutrons) are rearranged but conserved

36. Nuclear Reactions Beta emission
Note that mass number (A) is unchanged and atomic number (Z) goes up by 1.

37. Other Types of Nuclear Reactions
Positron (0+1b): a positive electron
207
Electron capture: the capture of an electron

38. Learning Check
What radioactive isotope is produced in the following bombardment of boron?
10B He ? n

39. Write Nuclear Equations!
Write the nuclear equation for the beta emitter Co-60.

40. Group Practice Work some problems together using ELMO
See Nuclear Equations Worksheet – page 4 of Flinn ChemTopicTM Labs book (vol. 18)

41. Independent Practice Set
Balancing Nuclear Equations – 1
Balancing Nuclear Equations – 2 (Word Problems)

42. Nuclear Stability Half-Life
Part III
Nuclear Stability
Half-Life

43. Introduce Half-Life with Lab
Half-Life of M&Ms (TAMU handout) or
Half-Life of Licorice (TAMU Handout) or
Half-Life with Pennies
IPC Lab Manual – pages 152 & 153

44. Nuclear Stability
Depends on the neutron to proton ratio.

45. Band of Stability
Number of Neutrons, (N)
Number of Protons (Z)

46. What happens to an unstable nucleus?
They will undergo decay
The type of decay depends on the reason for the instability

47. What type of decay will happen if the nucleus contains too many neutrons?
Beta Decay

48. Example: C  N + e In N-14 the ratio of neutrons to protons is 1:1 14
C  N e
In N-14 the ratio of neutrons to protons is 1:1 6 -1 7

49. Nuclei with atomic number > 83 (Bismuth) are radioactive

50. Radioactive Half-Life (t1/2 ):
Through study of radioactive isotopes, scientists have defined the rate of instability as half-life
In other words…. The time for half of the radioactive nuclei in a given sample to undergo decay

51. Common Radioactive Isotopes
Isotope Half-Life Radiation Emitted
Carbon ,730 years b, g
Radon days a
Uranium x 108 years a, g
Uranium x 109 years a

52. Radioactive Half-Life
After one half life there is 1/2 of original sample left.
After two half-lives, there will be
1/2 of the 1/2 = 1/4 the original sample.
After three half-lives, there will be 1/2 of the 1/4 (or 1/8) the original sample
….And so on….

53. Graph of Amount of Remaining Nuclei vs Time
A=Aoe-lt A

54. Half-Life Related Calculations
How to calculate number of half-lives (1/2 x 1/2x…)
How to calculate how old something is (no. of half-lives x time per half-life)
Calculate amount remaining (A) after a certain number of half-lives
A = Ao (where Ao = original amount)
2n (where n = no. of half-lives)
Calculate percentage remaining
__1_x 100%
2n (where n = no. of half-lives)

55. Example
You have 100 g of radioactive C-14. The half-life of C-14 is 5,730 years.
How many grams are left after one half-life? Answer: 100 g
50 g
How many grams are left after two half-lives?
25 g

56. Problem A sample of 3x107 Radon atoms are trapped
in a basement that is sealed. The half-life of
Radon is 3.83 days. How many radon atoms
are left after 31 days?
answer:1.2x105 atoms

58. Group and Independent Practice
Determining Half-Lives Practice Set
Practice 2 of problems as a group

59. Part IV Fission and Fusion

60. From Bill Nye the Science Guy
Nuclear Power – link to Discovery Education website

61. FISSION

62. Nuclear Fission

63. Nuclear Fission Fission is the splitting of atoms
These are usually very large, so that they are not as stable
Fission chain has three general steps:
1. Initiation. Reaction of a single atom starts the chain (e.g., 235U + neutron)
2. Propagation. 236U fission releases neutrons that initiate other fissions
3. Produces enormous amounts of energy

64. Nuclear Fission & POWER
Currently about 103 nuclear power plants in the U.S. and about 435 worldwide.
17% of the world’s energy comes from nuclear.

65. Figure 19.6: Diagram of a nuclear power plant.

66. Fission Benefits Concerns
A lot of energy can be produced from a small amount of raw material
1 ton of nuclear material = 1 million tons of coal or 1 million barrels of oil
Clean source of energy generation – not air polluting like fossil fuels
Long term source of fuel
Concerns
Safety accidents have potential for horrendous harm (immediate and long term, such as cancer)
No good way to dispose of high level nuclear waste
Expensive construction and maintenance costs

67. FUSION

68. Nuclear Fusion Fusion small nuclei combine 2H + 3H 4He + 1n + 1 1 2 0
Occurs in the sun and other stars
Energy

69. Nuclear Fusion Fusion Excessive heat can not be contained
Attempts at “cold” fusion have FAILED.
“Hot” fusion is difficult to contain

70. Fusion Benefits Concerns
A lot of energy can be produced from a small amount of raw material
1 ton of nuclear material = 1 million tons of coal or 1 million barrels of oil
Clean source of energy generation – not air polluting like fossil fuels
Long term source of fuel
Doesn’t create hazardous radioactive wastes as does nuclear fission
Concerns
Occur at extremely high temperatures – like that of sun
Cannot sustain the reactions long enough to be useful for power generation
Safety accidents have potential for horrendous harm (immediate and long term, such as cancer)
Expensive construction and maintenance costs

71. Part V Uses of Nuclear Chemistry

73. Radiocarbon Dating
Radioactive C-14 is formed in the upper atmosphere by nuclear reactions initiated by neutrons in cosmic radiation
14N + 1on ---> 14C + 1H
The C-14 is oxidized to CO2, which circulates through the biosphere.
When a plant dies, the C-14 is not replenished.
But the C-14 continues to decay with t1/2 = 5,730 years.
Activity of a sample can be used to date the sample.

74. Nuclear Medicine: Imaging
Thyroid imaging using Tc-99m

75. Food Irradiation
Food can be irradiated with g rays from 60Co or 137Cs.
Irradiated milk has a shelf life of 3 mo. without refrigeration.
USDA has approved irradiation of meats and eggs.

76. Part VI Hazards of Radiation

77. Effects of Radiation

78. Summary Nuclear Radiation can be naturally occurring or man-made
Most of radiation we are exposed to is naturally occurring – alpha rays
Alpha Radiation – weakest (blocked by paper or cloth)
Beta Radiation – medium (blocked by wood or foil)
Gamma Radiation – strongest (blocked by lead or concrete)
Key Nuclear Science Pioneers – Henri Beckerel, Marie and Pierre Curie

79. Summary
How to Write Nuclear Notation - see blue graphic organizer
Symbols for:
Beta Particles Alpha Particles
Positrons Neutrons
Gamma Rays γ
Atomic Mass
Element symbol
Atomic No. 1n

80. Summary Balancing Nuclear Equations (Law of Conservation of Mass)
Add coefficients in front of nuclear particles

81. SUMMARY - Half-Life Calculations
How to calculate number of half-lives (1/2 x ½ x…) or
1/amount remaining (as decimal or fraction) = 2n where n = no. half-lives
remember percent remaining = 100 – percent decayed
How to calculate how old something is (no. of half-lives x time per half-life)
Calculate amount remaining (A) after a certain number of half-lives
A = Ao (where Ao = original amount)
2n (where n = no. of half-lives)
Calculate percentage remaining
__1_x 100%
2n (where n = no. of half-lives)

82. Summary Describe the difference between: fission (splitting atoms)
3 steps
Initiation
Propagation
Production of large amounts of energy
fusion (combining nuclei)
Describe the pros and cons of each
Describe examples of fission and fusion
Examples of beneficial and harmful radiation sources
Power generation
Medical imaging, diagnostics, disease treatments
Food safety
Other – historical dating, smoke detectors, etc.
Know what percentage of US and world energy comes from nuclear material. Know the country that leads in nuclear usage.

83. Extra
Discovery Learning Video – Chemistry Connections: Nuclear Changes
Radioactivity Homework