Chapter 7, Problem 107A

Interpretation Introduction

Interpretation: The number of protons, electrons, and neutrons in each of the three isotopes of oxygen is to be stated.

Concept Introduction : Isotopes are species that have the same atomic number but have different atomic masses. Some elements have isotopes with different abundance percentages.

Answer to Problem 107A

The electrons, neutrons, and protons in three isotopes of oxygen are:

Isotope	Number of electrons	Atomic number	Number of protons	Mass number	Number of neutrons = Mass number − number of protons
${}_{\text{8}}^{\text{16}}\text{O}$	8	8	8	16	16 − 8 = 8
${}_{\text{8}}^{\text{17}}\text{O}$	8	8	8	17	17 − 8 = 9
${}_{\text{8}}^{\text{18}}\text{O}$	8	8	8	18	18 − 8 = 10

Explanation of Solution

There are three isotopes of oxygen: ${}_{\text{8}}^{\text{16}}\text{O,}{}_{\text{8}}^{\text{17}}\text{O,}{}_{\text{8}}^{\text{18}}\text{O}$ . The atomic number of oxygen is 8. It is equal to the number of protons and electrons.

The mass number is equal to the sum of protons and neutrons. The electrons, neutrons and protons in three isotopes of oxygen are:

Isotope	Number of electrons	Atomic number	Number of protons	Mass number	Number of neutrons = Mass number − number of protons
${}_{\text{8}}^{\text{16}}\text{O}$	8	8	8	16	16 − 8 = 8
${}_{\text{8}}^{\text{17}}\text{O}$	8	8	8	17	17 − 8 = 9
${}_{\text{8}}^{\text{18}}\text{O}$	8	8	8	18	18 − 8 = 10