Structure and Properties of the Nucleus

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Phosphorescent materials continue to glow after
the lights are turned off. How can you use the
model of an atom to explain this?
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Structure and Properties of the Nucleus
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Nucleons
Proton is the nucleus of the simplest atom,
hydrogen. It has positive charge (e) and mass
mp1.6726x10-27 kg. Neutron is electrically
neutral and has mass mn1.6749x10-27 kg
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Nuclei that contain the same number of protons
but different number of neutrons are called
isotopes.
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Nuclear Radii
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Atomic Mass Unit
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Binding Energy and Nuclear Forces
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The total mass of a stable nucleus is always less
than the sum of the masses of its constituent
protons and neutrons.
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The total energy represents the amount of energy
that must be put into a nucleus in order to break
it apart into its constituent protons and
neutrons.
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To be stable, the mass of nucleus must be less
than that of constituent nucleons, so that energy
input is needed to break it apart.
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Radioactivity
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Radioactivity is the result of the disintegration
or decay of instable element.
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Alpha Decay
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Smoke Detectors
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Transmutation
parent daughter
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Q-Value
The energy released is called the disintegration
energy, Q or Q-value
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Beta Decay
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Gamma Decay
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• Which of the three types of radiation will
  interact with electric field?
• Why do beta rays and alpha rays deflect in
  opposite directions when moving through a
  magnetic field?

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Baby-Quiz

1. Where would you most likely find an electron in
   the first excited state for a one-dimensional
   box?
2. Why do some minerals glow when they are
   illuminated with ultraviolet light?
3. The wavelength of red light is 600 nm. An
   electron with a speed of 1.2 km/s has the same
   wavelength. Will the electron look red? Explain.
4. An electron and proton have the same speeds.
   Which has the longer wavelength? Why?