MODES OF RADIOACTIVE DECAY
DOE-HDBK-1019/1-93
Atomic and Nuclear Physics
MODES OF RADIOACTIVE DECAY
Most atoms found in nature are stable and do not emit particles or energy that
change form over time. Some atoms, however, do not have stable nuclei. These
atoms emit radiation in order to achieve a more stable configuration.
EO 2.1
DESCRIBE the following processes:
a.
Alpha decay
d.
Electron capture
b.
Beta-minus decay
e.
Internal conversions
c.
Beta-plus decay
f.
Isomeric transitions
EO 2.2
Given a Chart of the Nuclides, WRITE the radioactive decay
chain for a nuclide.
EO 2.3
EXPLAIN why one or more gamma rays typically accompany
particle emission.
EO 2.4
Given the stability curve on the Chart of the Nuclides,
DETERMINE the type of radioactive decay that the nuclides in
each region of the chart will typically undergo.
Stability of Nuclei
As mass numbers become larger, the ratio of neutrons to protons in the nucleus becomes larger
for the stable nuclei. Non-stable nuclei may have an excess or deficiency of neutrons and
undergo a transformation process known as beta (b) decay. Non-stable nuclei can also undergo
a variety of other processes such as alpha (a) or neutron (n) decay. As a result of these decay
processes, the final nucleus is in a more stable or more tightly bound configuration.
Natural Radioactivity
In 1896, the French physicist Becquerel discovered that crystals of a uranium salt emitted rays
that were similar to x-rays in that they were highly penetrating, could affect a photographic
plate, and induced electrical conductivity in gases. Becquerel's discovery was followed in 1898
by the identification of two other radioactive elements, polonium and radium, by Pierre and
Marie Curie.
NP-01
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