Question

Chlorine exists in two isotopic forms `Cl-37` and Cl-35 but its atomic mass is 35.5. this indicates the ratio of Cl-37 and Cl-35 is appromimately
A. `1:2`
B. `1:1`
C. `1:3`
D. `3:1`

Answer 1

The fractional atomic mass (35.5) of chlorine is due to the fact that in ordinary chlorine atom Cl-37 and Cl-35 are present in the ratio of 1:3
`therefore` Average atomic mass of `Cl=(3xx35+1x x37)/(4)=35.5` amu