Chemistry
Answered
Why is atomic mass not always a whole number?
Why do we have atomic masses like 35.5 u for chlorine?
Answers (1)
Most elements exist as a mixture of isotopes. Chlorine has two stable isotopes: Cl-35 (~75%) and Cl-37 (~25%). The atomic mass is a weighted average: (35×0.75)+(37×0.25)=35.5 u.
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