Unit 5: Nuclear Chemistry Topic 12 in review book ...
Transcript of Unit 5: Nuclear Chemistry Topic 12 in review book ...
Radioactivity and Decay 2019.notebook
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Unit 5: Nuclear Chemistry
Aim: Introduction to radioactivity and decay particles
Topic 12 in review book
Reference Tables Used: Table N and Table O
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A radioactive isotope (radioisotope) is injected into a patient through an IV (intravenously).
Approximately 30 60 minutes later a camera takes a scan of the patient and an image of the kidneys are produced.
Question: How is it possible to see such a clear image of a persons kidneys buried deep within the body?
Radioactivity and Decay 2019.notebook
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Element Stability
• Binding energyenergy that binds the nucleons of the nucleus together.
• Stable nuclei of elements have a proton to neutron ratio of 1:1 or close to it.
• Unstable nuclei of elements have a larger p to n ratio than 1:1
> The protons and neutrons exist in a balance that stabilizes the nuclear force.
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Radioactive Elements
• Elements with atomic # 83 or greater are unstable and only exist as radioisotopes (Bismuth and up).
• Radioisotope: isotope of an element with an unstable nucleus.
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What is Radioactivity?Unstable nuclei are radioactive and will decay through natural transmutation.
• Natural transmutation: when an unstable nucleus spontaneously decays and mutates to become a more stable nucleus.
238U 4He + 234Th92 2 90
• Uranium238 nucleus is unstable and will decay by releasing an alpha particle (Table N decay mode) and transmutates into Thorium234.
Mass # Mass #
Charge Charge
• The mass number and charge are conserved. (equal on both sides of the nuclear equation).
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Decay Particles Table O
Name Symbol Strength (penetrating power)
Fill in the notation for the three radioactive particles listed below using Table O.
alpha Weakest
beta Moderate stronger than alpha. weaker than gamma
gamma Strongest penetrating power of all particles.
The radioactive particles can be found in Reference Table O.
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Alpha decay the emission of an alpha particle by the nucleus. The mass decreases by 4 and the atomic number decreases by 2.
Pu240
94 He4
2 U236
92+Equation:
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Beta decay (β): the emission of an electron. The atomic number increases by 1 and mass number remains the same.
Co137
55e0
1Ni137
56+Equation:
Radioactivity and Decay 2019.notebook
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Positron decay (β+): the nucleus gives off a positron. The atomic number decreases by 1 and the mass remains the same.
Na22
11 e0+1 Ne
22
10+Equation:
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Gamma decay emission of pure energy in the form of a gamma particle. The mass number and atomic number remain the same.
Co60
270
0Co60
27+Equation: γ