Question

what is relative weight and why is it important to the calculation of atomic mass?

Answer 1

relative weight is the weight of an atom when you take into consideration its isotopes. Naturally occurring elements are often found naturally occurring in different isotopes (more or less neutrons). For example if you dig for a sample of carbon you might have a certain percentage of carbon 12, carbon 13, and carbon 14. they all have the same number of protons but they have different number of neutrons. this causes the weight of the atoms to differ. So the atomic weights listed in the chemistry periodic table takes into consideration the percentage found empirically. So for example if a sample of carbon has 99% carbon 12, and 1% carbon 12 ... bleh this is boring