Chapter 2, Problem 2.20QP

(a)

Interpretation Introduction

Interpretation: The number of neutrons, protons and electrons to be calculated in a given atoms.

Concept introduction: The center of the atom is known as nucleus which consists of neutrons and protons. The electron revolves around the nucleus in different orbits.

To determine: The number of neutrons, protons and electrons in a given atom.

Answer to Problem 2.20QP

Solution

The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{6}$, $\underset{\_}{5}$ and $\underset{\_}{5}$, respectively.

Explanation of Solution

Explanation

The atomic number of ${}^{11}\text{B}$ is $5$ and atomic mass is $11$.

Calculate the number of neutrons by formula,

$\text{Number}\text{of}\text{neutrons}=\text{atomic}\text{mass}-\text{atomic}\text{number}$

Substitute value of atomic number and atomic mass in above formula,

$\begin{array}{c}\text{Number}\text{of}\text{Neutrons}=11-5\\ =6\end{array}$

Therefore, the number of neutrons are $\underset{\_}{6}$.

The number of proton is equal to the atomic number of element. Therefore, the number of protons in ${}^{11}\text{B}$ are $\underset{\_}{5}$.

The number of electrons is equal to atomic number or number of protons. Therefore, the number of electrons in ${}^{11}\text{B}$ are $\underset{\_}{5}$.

(b)

Interpretation Introduction

To determine: The number of neutrons, protons and electrons in a given atom.

Answer to Problem 2.20QP

Solution

The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{10}$, $\underset{\_}{9}$ and $\underset{\_}{9}$, respectively.

Explanation of Solution

Explanation

The atomic number of ${}^{19}\text{F}$ is $9$ and atomic mass is $19$.

Calculate the number of neutrons by formula,

$\text{Number}\text{of}\text{neutrons}=\text{atomic}\text{mass}-\text{atomic}\text{number}$

Substitute value of atomic number and atomic mass in above formula,

$\begin{array}{c}\text{Number}\text{of}\text{Neutrons}=19-9\\ =10\end{array}$

Therefore, the number of neutrons are $\underset{\_}{10}$.

The number of proton is equal to the atomic number of element. Therefore, the number of protons in ${}^{19}\text{F}$ are $\underset{\_}{9}$.

The number of electrons is equal to atomic number or number of protons. Therefore, the number of electrons in ${}^{19}\text{F}$ are $\underset{\_}{9}$.

(c)

Interpretation Introduction

To determine: The number of neutrons, protons and electrons in a given atom.

Answer to Problem 2.20QP

Solution

The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{78}$, $\underset{\_}{53}$ and $\underset{\_}{53}$, respectively.

Explanation of Solution

Explanation

The atomic number of ${}^{131}\text{I}$ is $53$ and atomic mass is $131$.

Calculate the number of neutrons by formula,

$\text{Number}\text{of}\text{neutrons}=\text{atomic}\text{mass}-\text{atomic}\text{number}$

Substitute value of atomic number and atomic mass in above formula,

$\begin{array}{c}\text{Number}\text{of}\text{Neutrons}=131-53\\ =78\end{array}$

Therefore, the number of neutrons are $\underset{\_}{78}$.

The number of proton is equal to the atomic number of element. Therefore, the number of protons in ${}^{131}\text{I}$ are $\underset{\_}{53}$.

The number of electrons is equal to atomic number or number of protons. Therefore, the number of electrons in ${}^{131}\text{I}$ are $\underset{\_}{53}$.

(d)

Interpretation Introduction

To determine: The number of neutrons, protons and electrons in a given atom.

Answer to Problem 2.20QP

Solution

The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{136}$, $\underset{\_}{86}$ and $\underset{\_}{86}$, respectively.

Explanation of Solution

Explanation

The atomic number of ${}^{222}\text{Rn}$ is $86$ and atomic mass is $222$.

Calculate the number of neutrons by formula,

$\text{Number}\text{of}\text{neutrons}=\text{atomic}\text{mass}-\text{atomic}\text{number}$

Substitute value of atomic number and atomic mass in above formula,

$\begin{array}{c}\text{Number}\text{of}\text{Neutrons}=222-86\\ =136\end{array}$

Therefore, the number of neutron is $\underset{\_}{136}$.

The number of proton is equal to the atomic number of element. Therefore, the number of protons in ${}^{222}\text{Rn}$ are $\underset{\_}{86}$.

The number of electrons is equal to atomic number or number of protons. Therefore, the number of electrons in ${}^{222}\text{Rn}$ are $\underset{\_}{86}$.

Conclusion

1. a. The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{6}$, $\underset{\_}{5}$ and $\underset{\_}{5}$, respectively.
2. b. The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{10}$, $\underset{\_}{9}$ and $\underset{\_}{9}$, respectively.
3. c. The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{78}$, $\underset{\_}{53}$ and $\underset{\_}{53}$, respectively.
4. d. The number of neutrons, number of protons and number of electrons for the given atom are $\underset{\_}{136}$, $\underset{\_}{86}$ and $\underset{\_}{86}$, respectively