Question

The relative mass of an atom or molecule is considered, by considering the mass of
a light atom & relating the mass of other atoms or molecules to it.​

Answer 1

Explanation:

Relative atomic mass (symbol: Ar) or atomic weight is a dimensionless physical quantity defined as the ratio of the average mass of atoms of a chemical element in a given sample to the atomic mass constant. The atomic mass constant (symbol: mu) is defined as being 112 of the mass of a carbon-12 atom.