Chapter 16.2, Problem 10R

To determine

To Explain: The difference in number of neutrons in chlorine-35 and chlorine-37.

Explanation of Solution

Introduction:

The average atomic mass of all the isotopes present in nature based on their abundance is known as the atomic mass of the element. 

Explanation: 

Chlorine-35 and chlorine-37 are the isotopes of chlorine element. The mass number is defined based on the number of protons and the number of neutrons (addition)

The number of protons in every chlorine atom is 17. So, Chlorine-35 and chlorine-37 contain equal number of protons but not neutrons. 

Chlorine-35 has 17 protons. So, it will have 18 neutrons (because 17 protons + 18 neutrons = 35). Similarly, chlorine-37 contains 17 protons. So, it will have 20 neutrons (17 protons + 20 neutrons = 37).

Conclusion: 

The chlorine atoms contain 18 neutrons or 20 neutrons that are based on isotopes of chlorine. (Chlorine-35 and Chlorine-37).