Nuclear Chemistry

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Nuclear Chemistry

• X-ray emission from the Sun in false color shows
  the swirling shapes of the high-temperature
  regions that often lie over sunspots. Nuclear
  processes taking place in the Sun release immense
  amounts of energy, a tiny fraction of which is
  intercepted by our planet and used to support
  life. Similar nuclear processes have many useful
  functions on Earth and can be beneficial if
  properly managed.

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Figure 22.11The numbers of stable nuclides for
even and odd numbers of neutrons and protons. By
far the greatest number of stable nuclides have
even numbers of protons and even numbers of
neutrons.
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Figure 22.12 The manner in which nuclear
stability depends on the atomic number and the
mass number. Nuclides along the narrow black band
(the band of stability) are generally stable.
Nuclides in the blue region are likely to emit a
? particle, and those in the red region are
likely to emit an ? particle. Nuclei in the pink
region are likely to emit either positrons or to
undergo electron capture. The magnified view of
the diagram near Z ? 60 shows the structure of
the band of stability.
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Figure 22.1 Henri Becquerel discovered
radioactivity when he noticed that an unexposed
photographic plate left near some uranium oxide
became fogged. This photograph shows one of his
original plates.
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Figure 22.2 Marie Sklodowska Curie (18671934).
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Figure 22.6 A nucleus can be pictured as a
collection of protons (pink) and neutrons (gray).
The protons repel one another electrically, but a
strong force that acts between all the particles
holds the nucleus together.
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Table 22.1 Types of Decay
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Figure 22.7 Alpha DecayWhen a nucleus ejects an
? particle, the atomic number of the atom
decreases by 2 and the mass number decreases by
4. The nucleons ejected from the upper nucleus
have been indicated by the blue boundary.
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Figure 22.8 Beta DecayWhen a nucleus ejects a ?
particle, the atomic number of the atom increases
by 1 and the mass number remains unchanged. The
neutron that we can regard as the source of the
electron is indicated by the blue boundary in the
upper part of the diagram.
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Figure 22.9 Electron Capture In electron
capture, a nucleus captures one of the
surrounding electrons. The effect is to convert a
proton (outlined in blue) into a neutron. As a
result, the atomic number decreases by 1 but the
mass number remains the same.
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Figure 22.10 In positron (??) emission, the
nucleus ejects a positron. The effect is to
convert a proton (outlined in blue) into a
neutron. As a result, the atomic number decreases
by 1, but the mass number remains the same
because the number of nucleons is unchanged.
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Figure 22.3The effects of an electric field on
nuclear radiation. Deflection toward the negative
plate identifies particles as positively charged,
and deflection toward the positive plate
identifies ? particles as negatively charged. The
fact that ? rays are not deflected toward either
plate identifies them as uncharged.
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Figure 22.4 Alpha Particles- An ? particle has
two positive charges and a mass number of 4. It
consists of two protons and two neutrons, and is
the same as the nucleus of a helium-4 atom.
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Figure 22.5 Gamma Radiation After a nucleus
decays, the nucleons remaining in the nucleus may
be left in a high-energy state, as shown by the
loose arrangement in the upper part of the
illustration. As the nucleons adjust to a lower
energy arrangement (bottom), the excess energy is
released as a ? ray photon.
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Figure 22.14 When a positively charged particle
approaches a nucleus, it is repelled strongly.
However, if it is traveling very fast, it can
reach the nucleus before the repulsion turns it
aside and a nuclear reaction may occur.
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Figure 22.15 An aerial view of the Fermi
National Accelerator Laboratory in Batavia,
Illinois. The largest circle is the main
accelerator three experimental lines are
tangential to it.
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Figure 22.20 The exponential decay of the number
of radioactive nuclei in a sample implies that
the activity of the sample also decays
exponentially with time. The curve is
characterized by the half-life, t1/2.
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Various ½ lives
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Figure 22.13 The uranium-238 decay series. The
times are the half-lives of the nuclides (see
Section 22.7).
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Figure 22.21 A map of the region near the
Chernobyl nuclear power plant. The colors
indicate the relative intensity of radiation
remaining in the soil. Areas with the darkest
colors are uninhabitable.
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Figure 22.22 In the modern version of the
carbon-14 dating technique, a mass spectrometer
is used to determine the proportion of carbon-14
nuclei in the sample relative to the number of
carbon-12 nuclei.
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Investigating Matter 22.1 (a)An iodine-123 scan
of a normal liver. Notice how clearly the shape
of the organ is revealed by the radioisotope. The
orange bean-shaped object is the gallbladder.
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Investigating Matter 22.1 (b)This facility at
Lawrence Livermore Laboratory is used to study
the irradiation of food. A container of fruit is
being lowered into a pool containing an
accelerator that generates radiation. The water
protects the technician from the harmful effects
of the radiation.