Final answer:
The atomic mass of chlorine can be calculated using the weighted average of the masses of its isotopes, chlorine-35 and chlorine-37.
Step-by-step explanation:
The atomic mass of an element can be calculated by taking the weighted average of the masses of its isotopes, considering both their abundances and masses. In this case, we have chlorine with two isotopes: chlorine-35 (75.77% abundance and 35 amu mass) and chlorine-37 (24.23% abundance and 37 amu mass). To calculate the atomic mass, we multiply the fraction of each isotope by its mass and sum them up. So, (0.7577 x 35) + (0.2423 x 37) = 35.48 amu.