Mass = # of protons + # of neutrons
Average atomic mass = (% abundance*atomic mass of isotope) + (% abundance*atomic mass of isotope)
Density= mass/volume (heart)
Percent error = |Measure value-accepted value/ accepted value| * 100
Half life = m2=m1(1/2)(t²/t^1)
m2= mass remaining
m1= original mass
t2= time
t1= half life