1. by what are isotopes identified? a. mass numbers b. atomic masses c. atomic mass units d. average atomic masses
and
2. uranium atoms each have 92 protons. how many protons does each u-238 atom have? a.92 b.146 c.238 d.330
and
3. chlorine atoms each have 17 protons. how many neutrons does each cl-37 atom have? a.17 b.20 c.37 d.54