Anyone know exactly where the numbers came from originally to define the Atomic Mass Units?
Mendelev knew them in 1869
Jons Jakob Berzelius ran experiments and using his experimental results he determined the atomic weights of nearly all the elements then known. They were whole numbers. If you look in the literature they report the value for Carbon as 12 and the value for the Carbon 13 isotope as 13.003 It is those two values that they multiply by the percent abundance and then use to calculate the average mean value of 12.0107 for Carbon. But where did the .003 come from for Carbon 13?
Who put together those fractional components and how did they arrive at them?