how do an element's mass related to the abundance of its isotopes?

Answer 1

If I remember correctly, you can calculate the element's mass based on the abundance and masses of its isotopes. Skip to the end of the answer if you don't want to read the example, which I give you for reference. Example -- Say one element has an atomic mass on the periodic table of 21 g/mol. One isotope is at abundance 10% with mass 24 g/mol, another is at abundance 40% at mass 22, another is at abundance 40% at mass 20 and the last isotope is at abundance 10% with mass 18. So you calculate the overall mass of the following using the relative weights of the isotopes: (.10)*24 + (.40)*22 + (.40)*20 + (.10)*18 = 21 g/mol. This is a pretty simplified example as some elements have lots and lots of isotopes, but there you go. Essentially, the element's mass is the average of its isotopes, where the average is weighted for the isotopes' abundance.

Answer 2

We must assume that the actual mass of the three isotopes equals the nominal atomic weights given; for actual elements there is a modest variation. The problem can then be solved using the following equation: 95 x + 98 (1-2x) + 102 x = 98.1 and solving for x.

Answer 3

the more mass there is the more likely there is to be isotopes