Define relative atomic mass.

Explanation

The relative atomic mass of element mass of element is defined as the ratio of mass of one atom of the element to the mass of `1//12^(th)` mass of one atom of carbon -12 Relative atomic mass `(A_r)`
`=("Mass of one atom of the element")/("Mass of "1//12^(th) " mass of one atom of Carbon-12")`
`=("Mass of one atom of the element")/(1.6605xx10^-27 Kg)`