Chlorine occurs in nature in two isotopic forms of masses 35 u and 37 u in the ratio of 3: 1 respectively. What is the average atomic mass of the Chlorine atom?

Step-by-step solution

The isotopes of chlorine are in the ratio 3: 1 . Therefore, in any sample of chlorine, ₁₇³⁵ CI will constitute 75 % and ₁₇³⁵ CI will constitute 25 % . The proportion in which the isotopes are found in nature is always constant. Therefore, in a sample of chlorine, the average atomic mass would be, The average atomic mass of chlorine aligned & = ( 35 75 100 )+ ( 37 25 100 ) & = 105 4 + 37 4 = 142 4 & =35.5 u aligned The average atomic mass of chlorine is equal to 35.5 u .