In the PhET simulation, make sure that the checkbox Stable/Unstable in the bottom right is checked. Using the PhET simulation as a reference, determine whether the following combinations of protons and neutrons form stable or unstable nuclei by adding protons and neutrons to the nucleus. Unstable nuclei will shake. If the Stable/Unstable checkbox in the lower right is also checked, the nuclei will be labeled Stable or Unstable. Sort the following combinations of protons and neutrons according to whether or not they form stable or unstable nuclei.