Question

The atomic mass of fluorine is 19.00 amu and that of copper is 63.55 amu. All fluorine atoms have a mass of 19.00 amu, and not a single copper atom has a mass of 63.55. Explain.

Answer 1

help please

Answer 2

mass number... you get the mass number by adding number of protons and neutrons of that atom and average the mass of all isotopes because isotopes have different number of neutrons, so fluorine and copper have different number of protons and neutrons and hence different masses