Nuclear Decay (Radioactivity)

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Nuclear Decay (Radioactivity)
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Subatomic particles

• Electron -negatively charged particle found
  outside the nucleus.
• Proton positively charged subatomic particle
  found inside the nucleus.
• Neutron Neutrally charged (no charge) subatomic
  particle found inside the nucleus.

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Some Surprises

• A neutron is a proton with a captured electron.
• A neutron can become a proton by losing that
  electron.
• That electron, when it comes flying out of the
  nucleus, will be called a beta particle. Its
  symbol is the Greek letter ß.

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Beta radiation

• What would happen to the nuclear make-up as a
  result of beta radiation? Consider carbon 14.

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Beta radiation

• What would happen to the nuclear make-up as a
  result of beta radiation? Consider carbon 14.

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Beta radiation

• How many protons does it have now?
• What is its mass number?

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Alpha Radiation

• An alpha (a) particle is the same as a helium
  nucleus and is therefore symbolized by

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Alpha Decay

• When an alpha particle is emitted from a nucleus,
  what is left? Consider Uranium 238.

X

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Which kind of decay is represented by each change?

• I 130 ? Xe 130
• Am-241 ? Np-237

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Three Kinds of Decay

• Alpha a helium nucleus, cannot penetrate paper.
• Beta - an electron which is emitted from the
  nucleus. Can penetrate paper, but cannot
  penetrate aluminum foil.
• Gamma ray not a particle. 50 emitted will
  penetrate 1cm of lead.