Chapter 6, Problem 99A

(a)

Interpretation Introduction

Interpretation: To name and determine no. of neutrons in the isotope

Concept introduction:

Isotopes are 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 99A

Name of the isotope is silver

No. of neutrons is 62

Explanation of Solution

Given isotope: $\text{A}\text{g}$

Name of the element is silver.

The atomic number is 47. The atomic number is no. of protons.

The mass number is 109.

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,

  $\begin{array}{c}\text{109}=47+\text{no}\text{. of neutrons}\\ \text{no}\text{. of neutrons}=109-47\\ =\text{62}\end{array}$

So, no. of neutrons is 62.

(b)

Interpretation Introduction

Interpretation: To name and determine no. of electrons in the 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 99A

Name of the isotope is tin.

No. of protons is 50.

Explanation of Solution

Given isotope: $\text{S}\text{n}$

The atomic number is 50. The atomic number is no. of protons.

So, no. of protons is 50.

(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 99A

Name of the isotope molybdenum.

No. of electrons is 42.

Explanation of Solution

Given isotope: $\text{M}\text{o}$

The atomic number is 42. The atomic number is no. of protons.

In any element no. of protons and neutrons are the same.

So, no. of electrons is 42.

(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 99A

Name of the isotope scandium.

No. of electrons is 21.

Explanation of Solution

Given isotope: $\text{S}\text{c}$

The atomic number is 21. The atomic number is no. of protons.

In any element no. of protons and neutrons are the same.

So, no. of electrons is 21.