A question about the element Neon
Posted: Thu Dec 10, 2009 11:59 am
How do you calculate the average atomic mass for neon if its abundance in nature is 90.5% neon-20, 0.3% neon-21, and 9.2% neon-22?
Hi,
To calculate the atomic weight you form the sum of mole fractions of isotope times isotopic mass:
20.18=20*0.905+21*0.003+22*0.092
To be more accurate you must use the exact isotopic weights of each isotope, which are not exactly 20,21 and 22., plus there are other isotopes as well.
Best regards,
Barrett L. Tomlinson