Radioactive Decay Chart

by

Marilynn Stone

This SMART website is hosted by the Illinois Institute of Technology


      When a radioactive substance decays, it emits particles from the nucleus in a effort to become a stable atom.  The particles that are emitted are either an alpha particle (α) particle, a beta particle (β), or a gamma ray (γ).

An alpha particle is equivalent to a Helium nucleus  2He4.  When this particle is emitted, the atomic number of the atom decreases by two and the atomic mass decreases by 4.

A beta particle is equivalent to an electron -1e0.  When this particle is emitted, the atomic number or the atom increases by one and the atomic mass stays the same.

A gamma ray does not change the atom.

To fill in the chart, a periodic table of the elements is needed.  If an alpha particle is emitted, the atomic number decreases by 2 which will produce a new element. The new element is determined by the atomic number.  The atomic mass will decrease by 4.  Just fill in the new element, atomic number and atomic mass in the circle.

If a beta particle is emitted, the atomic number increases by 1 which will produce a new element.  The new element is determined by the atomic number.  The atomic mass is unchanged.  Just fill in the new element, atomic number and atomic mass in the circle.

When you have finished, radioactive uranium will become stable lead.                                                                                                                                      

           

                                                                                                                                                                     

                                                 


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