Chapter 4.3, Problem 18SP

(a)

Interpretation Introduction

Interpretation : The number of neutrons present in each of the elements is to be identified.

Concept Introduction :

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

Answer to Problem 18SP

The neutrons present in ${}_{35}^{80}\text{Br}$ is $\text{45}$ .

Explanation of Solution

The count of protons present in the nucleus of the atom gives the atomic number (Z).

The count of protons and neutrons present in the nucleus of the atom gives the mass number (A).

The general representation symbol of an element is given as ${}_{\text{Z}}^{\text{A}}\text{X}$ .

Where, $X$ is the element, $Z$ is the atomic number, and $A$ is the atomic number.

The number of neutrons in an element is the difference between the mass number and the number of protons in an element.

The formula to calculate the number of neutrons is given as

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

In the given element ${}_{35}^{80}\text{Br}$ , the mass number is $80$ and the number of protons is $35$ .

Substitute the values in the above formula to calculate the number of neutrons.

  $\begin{array}{c}\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}\\ \text{=}\text{80}-35\\ =45\end{array}$

The number of neutrons in ${}_{35}^{80}\text{Br}$ is $\text{45}$ .

(b)

Interpretation Introduction

Interpretation : The number of neutrons present in each of the elements is to be identified.

Concept Introduction :

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

Answer to Problem 18SP

The neutrons present in ${}_{16}^{32}\text{S}$ is $16$ .

Explanation of Solution

The count of protons present in the nucleus of the atom gives the atomic number (Z).

The count of protons and neutrons present in the nucleus of the atom gives the mass number (A).

The general representation symbol of an element is given as ${}_{\text{Z}}^{\text{A}}\text{X}$ .

Where, $X$ is the element, $Z$ is the atomic number, and $A$ is the atomic number.

The number of neutrons in an element is the difference between the mass number and the number of protons in an element.

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

In the given element ${}_{16}^{32}\text{S}$ , the mass number is $32$ and the number of protons is $16$ .

Substitute the values in the above formula to calculate the number of neutrons.

  $\begin{array}{c}\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}\\ \text{=}32-16\\ =16\end{array}$

The number of neutrons in ${}_{16}^{32}\text{S}$ is $16$ .

(c)

Interpretation Introduction

Interpretation : The number of neutrons present in each of the elements is to be identified.

Concept Introduction :

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

Answer to Problem 18SP

The neutrons present in ${}_{47}^{108}\text{Ag}$ is $61$ .

Explanation of Solution

The count of protons present in the nucleus of the atom gives the atomic number (Z).

The count of protons and neutrons present in the nucleus of the atom gives the mass number (A).

The general representation symbol of an element is given as ${}_{\text{Z}}^{\text{A}}\text{X}$ .

Where, $X$ is the element, $Z$ is the atomic number, and $A$ is the atomic number.

The number of neutrons in an element is the difference between the mass number and the number of protons in an element.

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

In the given element ${}_{47}^{108}\text{Ag}$ , the mass number is $108$ and the number of protons is $47$ .

Substitute the values in the above formula to calculate the number of neutrons.

  $\begin{array}{c}\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}\\ \text{=}108-47\\ =61\end{array}$

The number of neutrons in ${}_{47}^{108}\text{Ag}$ is $61$ .

(d)

Interpretation Introduction

Interpretation : The number of neutrons present in each of the elements is to be identified.

Concept Introduction :

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

Answer to Problem 18SP

The neutrons present in ${}_{82}^{207}\text{Pb}$ is $125$ .

Explanation of Solution

The count of protons present in the nucleus of the atom gives the atomic number (Z).

The count of protons and neutrons present in the nucleus of the atom gives the mass number (A).

The general representation symbol of an element is given as ${}_{\text{Z}}^{\text{A}}\text{X}$ .

Where, $X$ is the element, $Z$ is the atomic number, and $A$ is the atomic number.

The number of neutrons in an element is the difference between the mass number and the number of protons in an element.

The formula to calculate the number of neutrons is given as:

  $\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}$

In the given element ${}_{82}^{207}\text{Pb}$ , the mass number is $207$ and the number of protons is $82$ .

Substitute the values in the above formula to calculate the number of neutrons.

  $\begin{array}{c}\text{Number of neutrons}\text{=}\text{Mass number}-\text{Number of protons}\\ \text{=}207-82\\ =125\end{array}$

The number of neutrons in ${}_{82}^{207}\text{Pb}$ is $125$ .