TOPIC: Radioactivity

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TOPIC Radioactivity Natural TransmuationsDo
Now Where on your reference table can you find
radioactive particles?
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• Not all isotopes are stable

Stable isotopes have 11 ratio of n0 to p
(for elements lt20) 1.51 ratio of n0 to p
(for elements gt20)
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Beyond Element 83 are very unstable (radioactive)

• No amount neutrons can hold nucleus together once
  it has 83 protons
• All Elements 83 and above on PT
• are radioactive
• Other elements may have radioactive isotopes
• 
  applet

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Radioisotopes- unstable nucleus they are
radioactive
the nucleus of element emits subatomic particles
and/or electromagnetic wavesby emitting these
particles,nucleus changes into different element
(its trying to become more stable)
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Radioactive Decay Series

• Sometimes 1 transmutation isnt enough to achieve
  stability
• Some radioisotopes go through several changes
  before they achieve stability (and are no longer
  radioactive)

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U-238 ? PB-206
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Transmutation-When an element turns into a
different element. This occurs when the number of
protons changes.
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These subatomic particles that are emitted were
discovered around 1900

• Alpha rays
• Beta rays
• Gamma rays

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(No Transcript)
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Radioactivity Rutherford again!
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Penetration Shielding
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2 Neutrons 2 Protons Charge 2 Mass 4amu
42He
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Beta Particle fast moving electron
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Transmutation

• 2 types
• Natural
• Artificial

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Natural Transmutation

• Happens all by itself (spontaneous)
• Not affected by anything in environment
• 1 term on reactant side
• Original isotope
• 2 terms on product side
• Emitted Particle
• New Isotope

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Natural Transmutation

• 16N ? 0e 16O

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2 terms on product side
1 term on reactant side
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Balancing Nuclear Equations

• 16N ? 0e 16O

Conservation of mass number 16 0 16
Conservation of atomic number 7 -1 8
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• 232Th ? 4He X

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Conservation of Mass Number sum of mass numbers
on left side must sum of mass numbers on right
side
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• 232Th ? 4He 228X

Conservation of Atomic Number sum of atomic
numbers on left side must sum of atomic numbers
on right side