Moles, Formulae and Equations

Abstract

The relative atomic mass, A_r, of an element is the number of times that the average mass of one of its atoms is greater than 1/12 of the mass of an atom of $\mathop {12}\limits_6 {\rm{C}}$. (For an explanation of the figures in $\mathop {12}\limits_6 {\rm{C}}$, see page 17.) The relative atomic mass is approximately equal to the mass number of the atom. Since it is a ratio, relative atomic mass has no units. Values of relative atomic masses are given on page 24.