More info about atomic weight: http://suzy.unl.edu/bruno/java/atomas.html

A text summary of the clickable map above, meant for web-crawlers and other automatic tools:
atomic weight characteristic of atom
atomic weight characteristic of isotope
atomic weight contrasts with molecular weight
atomic weight has example atomic wt O ~ 16
atomic weight has characteristic freq of isotopes affects averag
atomic weight approximately twice atomic number
atomic weight determined by # of neutrons & protons
atomic weight information provided in periodic table