12-08-2021, 07:27 AM
You want the value? 26.98 or do you want to know what it is? It is the average mass of all atoms of Al in their normal isotope ratio, and it is the mass of 6.23 x 10^23 atoms on the scale where an atom of carbon-12 isotope is taken as 12.000000000. This is very very easy to find in google!