Asked by Karen

Three isotopes of Neon occur naturally:

20Ne (mass = 19.9924 amu)
21Ne (mass = 20.9938 amu)
22Ne (mass = 21.9914 amu)

If the percent abundance of 21Ne is 0.2600, what is the percent abundance of 20Ne?

How do I set up for these type of problems. I tried just using two and realized that was wrong. I can't use (1-x) or x since I have more than what isotope so what do I do?
Answered by DrBob222
How about this?
20Ne + 21Ne + 22Ne = 100%
20Ne + 0.26 + 22Ne = 100% and
20Ne + 22Ne = 100-0.26 = 99.74%
Let x = 20Ne and 0.9974-x = 22Ne
Set your equation up as usual and solve for x and 0.9974-x.
Answered by Karen
ahh thank you so much!