Final answer:
Chlorine-35 and chlorine-37 are isotopes of chlorine, differing in their neutron counts. Chlorine-35 has 18 neutrons and chlorine-37 has 20, contributing to natural chlorine's average atomic mass of around 35.45 amu, based on their natural abundances of about 75.76% and 24.24%, respectively.
Step-by-step explanation:
The isotopes chlorine-35 and chlorine-37 are both forms of the element chlorine (Cl), but they differ in their number of neutrons. Chlorine has an atomic number of 17, meaning it always has 17 protons. Isotopes of an element have the same number of protons but different numbers of neutrons; chlorine-35 has 18 neutrons and chlorine-37 has 20 neutrons.
To determine the average atomic mass of chlorine, we use the percent abundances of its isotopes along with their atomic masses. The calculation is as follows:
Average atomic mass = (fraction of 35Cl × mass of 35Cl) + (fraction of 37Cl × mass of 37Cl).
Using the given values: (0.7577 × 34.969 amu) + (0.2423 × 36.966 amu) = 35.45 amu.
Therefore, the average atomic mass of chlorine is calculated to be approximately 35.45 amu, considering a natural abundance distribution of 75.76% for chlorine-35 and 24.24% for chlorine-37.