Chapter 10, Problem 19P

Interpretation Introduction

(a)

Interpretation:

Atomic number for each isotope of fluorine given below should be predicted.

  

Concept Introduction:

Atomic number of an atom is equal to the number of protons in it. Atomic number is represented by Z.

Answer to Problem 19P

The atomic number for isotope of fluorine A and B is 9.

Explanation of Solution

In the molecular model of fluorine, orange balls represent neutrons, whereas blue balls represent protons. Since the number of protons from given molecular models A and B is 9, the atomic number becomes 9 for A and B both, as the atomic number is equal to the number of protons in that atom.

  

Interpretation Introduction

(b)

Interpretation:

Mass number for each isotope of fluorine given below should be predicted.

  

Concept Introduction:

The mass number is equal to the number of protons and neutrons in an atom.

Answer to Problem 19P

The atomic number for isotope of fluorine A and B is 18 and 19 respectively.

Explanation of Solution

From the molecular model of an isotope of fluorine, the number of neutrons can be counted. Thus, the number of neutrons in A and B is 9 and 10 respectively.

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

For A and B, the mass number will be calculated as follows:

  $\begin{array}{c}\text{Mass}\text{number}\text{of}\text{}\text{A}\text{=}\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ \text{= 9 + 9}\\ \text{= 18}\end{array}$

  $\begin{array}{c}\text{Mass}\text{number}\text{of}\text{}\text{B}\text{= }\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ \text{= 9 + 10}\\ \text{= 19}\end{array}$

Interpretation Introduction

(c)

Interpretation:

Number of protons for each isotope of fluorine given below should be predicted.

  

Concept Introduction:

The number of protons is equal to the atomic number of that atom.

Answer to Problem 19P

The number of protons in isotope of fluorine A and B is 9.

Explanation of Solution

In the molecular model of fluorine, protons are represented by blue balls. Thus, the number of protons in A and B will be calculated by counting the number of blue balls in A and B in the given figure as follows:

  

  

Thus, the number of protons in A and B is 9.

Interpretation Introduction

(d)

Interpretation:

The number of neutrons for each isotope of fluorine given below should be predicted.

  

Concept Introduction:

The mass number is the sum of all the protons and neutrons present in an atom. Thus, the number of neutrons can be calculated simply by subtracting the number of protons from the mass number of that atom.

Answer to Problem 19P

The number of neutrons in A and B is 9 and 10 respectively.

Explanation of Solution

For A, the mass number and number of protons are 18 and 9 respectively. Thus, the number of neutrons in A will be calculated as follows:

  $\begin{array}{c}\text{Mass}\text{number}\text{of}\text{}\text{A}\text{=}\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ \text{18}\text{=}\text{9}\text{+}\text{Number}\text{of}\text{neutrons}\\ \text{Number}\text{of}\text{neutrons}\text{=}\text{18}\text{-}\text{9}\\ \text{= 9}\end{array}$

For B the mass number and number of protons are 19 and 9 respectively. Thus, the number of neutrons in B will be calculated as follows:

  $\begin{array}{c}\text{Mass}\text{number}\text{of}\text{}\text{B}\text{=}\text{Number}\text{of}\text{protons+Number}\text{of}\text{neutrons}\\ \text{19}\text{=}9\text{+}\text{Number}\text{of}\text{neutrons}\\ \text{Number}\text{of}\text{neutrons}\text{=}\text{19}\text{-}9\\ \text{= 10}\end{array}$

Interpretation Introduction

(e)

Interpretation:

The isotope symbol for each isotope of fluorine given below should be predicted.

  

Concept Introduction:

Isotopes are the compounds having the same atomic number but different atomic mass.

To write an isotope symbol atomic number (Z) is written on the lower left side and atomic mass(A) is written on the upper left side of an element.

Answer to Problem 19P

The isotope symbol for A and B is ${}_{\text{9}}^{\text{18}}\text{F}$ and ${}_{\text{9}}^{\text{19}}\text{F}$.

Explanation of Solution

For A, the mass number and atomic numbers are 18 and 9 respectively. Thus, the isotope symbol for A will be represented as follows:

  ${}_{\text{9}}^{\text{18}}\text{F}$

For B, the mass number and atomic numbers are 19 and 9 respectively. Thus, the isotope symbol for B will be represented as follows:

  ${}_{\text{9}}^{\text{19}}\text{F}$