1. What are the "true" values of atomic mass?It has been known for a long time that the relative atomic mass, Ar, of lead, Pb, changes slightly depending upon the origin of the lead as it is the end product of natural radioactive decay series. If the lead originates from an area rich in 238-U then the end product will be richer in 206-Pb whereas if the area was originally rich in 232-Th then the resulting lead will...