posted by Sara .
The atomic mass of chlorine is listed as 35.454 amu on the periodic table. It has two naturally occurring isotopes, CI-35 and CI-37. What are the approximate percentage of each?
If you want REAL numbers you can get them from www.webelements.com.
If you want to calculate them, you need to know the masses of the 35 and the 37.
x = fraction of the 35.
1-x = fraction of the 37
x(mass 35) + (1-x)(mass 37) = 35.454.