I am supposed to find the percent abundancies of two isotopes. I am given the masses of both isotopes, along with the atomic mass. (This is a fictional element with only those two isotopes.) I am not given percentages for either isotope... how do I solve this?

Question

I am supposed to find the percent abundancies of two isotopes.  I am given the masses of both isotopes, along with the atomic mass.  (This is a fictional element with only those two isotopes.)  I am not given percentages for either isotope... how do I solve this?

bobpursley · Answer

Well, if the Percent of A is A, then the percent of B is 1-A (decimal percents.) Then avgatomicmass=massA*precentA + massB(1-percentA) solve for percent of A.