2. Review Atomic Number (Z) – number of protons
Mass Number (A) – sum of protons and neutrons
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3. Radioactive Decay
Nucleus undergoes decomposition to form a different nucleus.
Nuclides with 84 or more protons are unstable.
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4. The Zone of Stability
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5. Types of Radioactive Decay
Alpha production (α):
Beta production (β):
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6. Types of Radioactive Decay
Gamma ray production (γ):
Positron production:
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7. Types of Radioactive Decay
Electron capture:
Inner-orbital electron
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8. Decay Series (Series of Alpha and Beta Decays)
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9. Balancing Nuclear Equations
Conserve mass number (A).
The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants. 1n U
235 92 + Cs
138 55 Rb 96 37
+ 2
= x1
Conserve atomic number (Z) or nuclear charge.
The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants. 1n U
235 92 + Cs
138 55 Rb 96 37
+ 2
= x0

10. Which of the following produces a particle? electron capture positron
CONCEPT CHECK!
Which of the following produces a particle?
electron capture
positron
alpha particle
beta particle
The correct answer is d. Go through the rest of the equations to identify these types of equations as well.
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11. 19.1
Balance the following nuclear equations (that is, identify the product X):
(a)
(b)

12. 19.1
Strategy
In balancing nuclear equations, note that the sum of atomic numbers and that of mass numbers must match on both sides of the equation.
Solution
(a) The mass number and atomic number are 212 and 84, respectively, on the left-hand side and 208 and 82, respectively, on the right-hand side. Thus, X must have a mass number of 4 and an atomic number of 2, which means that it is an α particle. The balanced equation is

13. 19.1
(b) In this case, the mass number is the same on both sides of the equation, but the atomic number of the product is 1 more than that of the reactant. Thus, X must have a mass number of 0 and an atomic number of -1, which means that it is a β particle. The only way this change can come about is to have a neutron in the Cs nucleus transformed into a proton and an electron; that is, (note that this process does not alter the mass number). Thus, the balanced equation is

14. Rate of Decay
Rate = kN
The rate of decay is proportional to the number of nuclides. This represents a first-order process.
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15. Half-Life
Time required for the number of nuclides to reach half the original value.
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16. Nuclear Particles To play movie you must be in Slide Show Mode
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17. Half-Life of Nuclear Decay
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18. EXERCISE!
A first order reaction is 35% complete at the end of 55 minutes. What is the value of k?
ln[A] = –kt + ln[A]o
ln(0.65) = –k(55) + ln(1)
k = 7.8 × 10-3 min-1
k = 7.8 x 10-3 min-1. If students use [A] = 35 in the integrated rate law (instead of 65), they will get k = 1.9 x 10-2 min-1.
Note: Use the red box animation to assist in explaining how to solve the problem.

19. Nuclear Transformation
The change of one element into another.
(Happens by bombarding the nucleus, here with alpha particle or another element)
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20. Accelerators like cyclotron and linear accelerators is used to bombard a nucleus with high velocity positive ion to produce other element
Neutrons are also used for this purpose

21. Measuring Radioactivity Levels
Geiger counter
Scintillation counter
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22. Geiger Counter To play movie you must be in Slide Show Mode
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23. Carbon–14 Dating Used to date wood and cloth artifacts.
Based on carbon–14 to carbon–12 ratio.
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24. Radiotracers
Radioactive nuclides that are introduced into organisms in food or drugs and whose pathways can be traced by monitoring their radioactivity.
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25. Radiotracers
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26. Energy and Mass
When a system gains or loses energy it also gains or loses a quantity of mass.
E = mc2
Δm = mass defect
ΔE = change in energy
If ΔE is negative (exothermic), mass is lost from the system.
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27. Binding Energy
The energy required to decompose the nucleus into its components.
Iron-56 is the most stable nucleus and has a binding energy of 8.79 MeV.
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28. 19.2
The atomic mass of is amu. Calculate the nuclear binding energy of this nucleus and the corresponding nuclear binding energy per nucleon.

29. 19.2
Strategy
To calculate the nuclear binding energy, we first determine the
difference between the mass of the nucleus and the mass of all the protons and neutrons, which gives us the mass defect. Next, we apply Equation (19.2) [ΔE = (Δm)c2].
Solution
There are 53 protons and 74 neutrons in the iodine nucleus.
The mass of atom is
53 x amu = amu
and the mass of 74 neutrons is
74 x amu = amu

30. 19.2
Therefore, the predicted mass for is = amu, and the mass defect is
Δm = amu amu
= amu
The energy released is
ΔE = (Δm)c2
= ( amu) (3.00 x 108 m/s)2
= x 1017 amu · m2/s2

31. 19.2
Let’s convert to a more familiar energy unit of joules. Recall that 1 J = 1 kg · m2/s2. Therefore, we need to convert amu to kg:
Thus, the nuclear binding energy is 1.73 x J . The nuclear binding energy per nucleon is obtained as follows:
(1.60 x J = 1 MeV)

32. Binding Energy per Nucleon vs. Mass Number
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33. Nuclear Fission and Fusion
Fusion – Combining two light nuclei to form a heavier, more stable nucleus.
Fission – Splitting a heavy nucleus into two nuclei with smaller mass numbers.
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34. Nuclear Fission To play movie you must be in Slide Show Mode
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35. Fission Processes
A self-sustaining fission process is called a chain reaction.
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36. Schematic of a Nuclear Reactor

37. Schematic Diagram of a Reactor Core
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38. Nuclear Fusion To play movie you must be in Slide Show Mode
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39. Biological Effects of Radiation
Depend on:
Energy of the radiation
Penetrating ability of the radiation
Ionizing ability of the radiation
Chemical properties of the radiation source
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40. rem (roentgen equivalent for man)
The energy dose of the radiation and its effectiveness in causing biologic damage must be taken into account.
Number of rems = (number of rads) × RBE
rads = radiation absorbed dose
RBE = relative effectiveness of the radiation in causing biologic damage

41. Effects of Short-Term Exposures to Radiation
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