Class will begin with a review and expansion of the atomic nucleus, protons, neutrons,mesons, and the strong force. Atomic mass and atomic number was discussed in relationship to the number of neutrons and protons in the nucleus, and the ratio of neutrons to protons which creates a stable nucleus. We discussed the definition of isotopes and the ratio of neutrons to protons which allow an isotope to remain stable. Ratios above that will lead to instability and decay. The 3 types of decay, being alpha, beta, and gamma rays were discussed and the symbols for each shown.