Radioactive Decay of Cesium-137

This video shows a sample of cesium-137 being tested for emission of radiation.  Nuclei of cesium-137 isotopes are unstable and will undergo a process of radioactive decay to form more stable isotopes.  Cesium-137 is formed during fission reactions of uranium-235 in nuclear power plants and nuclear weapons.


The equation that describes the radioactive decay of cesium is shown below.  The conversion of a neutron (from the cesium nucleus) to a proton causes the atomic number to increase from 55 to 56.  This leads to the formation of barium-137.  It's important to notice that the mass number stays the same in examples of beta decay.


137
Cs
→
137
Ba
+
0
e
55
56
-1

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