What is the difference between atomic mass and atomic weight?
Atomic weight (symbol: Ar) is a dimensionless physical quantity, the ratio of the average mass of atoms of an element (from a given source) to 1/12 of the mass of an atom of carbon-12. Atomic Mass:The atomic mass is the average mass of an element in atomic mass units (“amu”). Though individual atoms always have an integer number of atomic mass units, the atomic mass on the periodic table is stated as a decimal number because it is an average of the various isotopes of an element. Isotopes can have a weight either more or less than the average. The average number of neutrons for an element can be found by subtracting the number of protons (atomic number) from the atomic mass.
