nucleon
protons and neutrons together
rest energy
intrinsic amount of energy that is associated with mass
strong force
overcomes repulsive coulomb forces b/w protons in nucleus and hold it together: 10^38 times stronger than gravity, only effective over very short distances
valley of stability
<83 : more neutrons are needed to be added to stabilize, but they don’t fit
binding energy
difference in energy between bound by leans and unbound protons and neutrons
alpha decay
results in a He2 mass 4, and then another element you get from subtraction
beta decay
results in an electron and another element