ChemistryCode 5070
Relative masses of atoms and molecules
What this topic asks you to be able to do
- Describe relative atomic mass, Ar, as an element's average isotope mass, measured in units of 1/12th of the mass of one 12C atom
- Define relative molecular mass, Mr, as the total of the relative atomic masses. For ionic compounds, the quantity to use is called relative formula mass, Mr.