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 ?
36·1 u
35·5 u
36·5 u
35·1 u
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC NDA-2 – 2021
Average atomic mass = $(35 \text{ u} \times 3/4) + (37 \text{ u} \times 1/4)$
Average atomic mass = $(105/4) \text{ u} + (37/4) \text{ u}$
Average atomic mass = $(105 + 37)/4 \text{ u}$
Average atomic mass = $142/4 \text{ u}$
Average atomic mass = $35.5 \text{ u}$.