Question

Chlorine occurs in nature in two isotopic forms, with masses 35 u and 37 u in the percentage occurance of 75% and 25% respectively. What is the average atomic mass of chlorine atom?

• A. 35 amu
• B. 37 amu
• C. 35.5 amu
• D. 36 amu

Answer 1

The correct option is C 35.5 amu

The average atomic mass of chlorine atom, on the basis of above data, will be

$\Rightarrow 35\times \frac{75}{100}+37\times \frac{25}{100}\Rightarrow 35.5amu$