Predicting nuclear stability is important when determining whether or not a nuclear reaction can take place spontaneously.Use the following set of guidelines to predict the nuclear stability of the elements listed below.

1. Stable nuclei have a high neutron-to-proton ratio, greater than 1.25 beyond atomic number 40 and continuing to rise at higher atomic numbers.
2. The majority of stable nuclei have even numbers of neutrons and protons. Odd-even and even-odd combinations can be stable but stability is less likely.
3. Nuclei that have the magic numbers of 2, 8, 20, 28, 50, or 82 protons or 2, 8, 20, 28, 50, 82 or 126 neutrons are more stable than nuclei that do not contain these numbers.
4. Nuclei that have atomic numbers greater than 83 are unstable.Nuclei are considered stable if one or more criteria are met.