Chapter 6, Problem 98A

(a)

Interpretation Introduction

Interpretation: To determine the number of isotopes in an isotope.

Concept introduction:

Isotopes are any two or more different chemical forms of the same element that have the same number of protons but varying numbers of neutrons in their nucleus.

Answer to Problem 98A

So, no. of neutrons is 48.

Explanation of Solution

Given isotope: $\text{K}\text{r}$

The atomic number is 36. The atomic number is no. of protons.

The mass number is 84.

Expression for mass number is,

  $\text{mass number}=\text{no}\text{. of protons}+\text{no}\text{. of neutrons}$

So, calculate no. of neutrons as shown,

  $\begin{array}{c}\text{84}=36+\text{no}\text{. of neutrons}\\ \text{no}\text{. of neutrons}=84-36\\ =\text{48}\end{array}$

So, no. of neutrons is 48.

(b)

Interpretation Introduction

Interpretation: To determine the number of isotopes in an isotope.

Concept introduction:

Isotopes are any two or more different chemical forms of the same element that have the same number of protons but varying numbers of neutrons in their nucleus.

Answer to Problem 98A

So, no. of neutrons is 44.

Explanation of Solution

Given isotope: $\text{B}\text{r}$

The atomic number is 35. The atomic number is no. of protons.

The mass number is 79.

Expression for mass number is,

  $\text{mass number}=\text{no}\text{. of protons}+\text{no}\text{. of neutrons}$

So, calculate no. of neutrons as shown,

  $\begin{array}{c}\text{79}=35+\text{no}\text{. of neutrons}\\ \text{no}\text{. of neutrons}=79-35\\ =\text{44}\end{array}$

So, no. of neutrons is 44.

(c)

Interpretation Introduction

Interpretation: To determine the number of isotopes in an isotope.

Concept introduction:

Isotopes are any two or more different chemical forms of the same element that have the same number of protons but varying numbers of neutrons in their nucleus.

Answer to Problem 98A

So, no. of neutrons is 114.

Explanation of Solution

Given isotope: $\text{O}\text{s}$

The atomic number is 76. The atomic number is no. of protons.

The mass number is 190.

Expression for mass number is,

  $\text{mass number}=\text{no}\text{. of protons}+\text{no}\text{. of neutrons}$

So, calculate no. of neutrons as shown,

  $\begin{array}{c}\text{190}=76+\text{no}\text{. of neutrons}\\ \text{no}\text{. of neutrons}=190-76\\ =\text{114}\end{array}$

So, no. of neutrons is 114.

(d)

Interpretation Introduction

Interpretation: To determine the number of isotopes in an isotope.

Concept introduction:

Isotopes are any two or more different chemical forms of the same element that have the same number of protons but varying numbers of neutrons in their nucleus.

Answer to Problem 98A

So, no. of neutrons is 110.

Explanation of Solution

Given isotope: $\text{R}\text{e}$

The atomic number is 75. The atomic number is no. of protons.

The mass number is 185.

Expression for mass number is,

  $\text{mass number}=\text{no}\text{. of protons}+\text{no}\text{. of neutrons}$

So, calculate no. of neutrons as shown,

  $\begin{array}{c}\text{185}=75+\text{no}\text{. of neutrons}\\ \text{no}\text{. of neutrons}=185-75\\ =\text{110}\end{array}$

So, no. of neutrons is 110.