Question

The element chlorine (Cl) has two isotopes: chlorine‑35 and chlorine‑37. Approximately 75.5% of chlorine atoms have 18 neutrons and 17 protons, and the other 24.5% have 20 neutrons and 17 protons. Using the isotopic composition provided, calculate the average atomic mass of chlorine. Round your answer to the tenths place.

Answer 1

35.5 amu is the average atomic mass of chlorine

Step-by-step explanation:

Fractional abundance of chlorine‑35 = 75.5%

Fractional abundance of chlorine‑37 = 24.5%

Average atomic mass is equal to summation of products of all isotopes masses into their fractional abundance.

Average atomic mass = Σ(Mass of an isotope × fractional abundance)

Average atomic of chlorine :

`35 amu* 0.755+37 amu* 0.245=35.49 amu\approx 35.5 amu`

35.5 amu is the average atomic mass of chlorine