Chapter 2, Problem 2.23QP

Interpretation Introduction

Interpretation: The missing information from the given table is to be stated.

Concept introduction: The electrons, protons, and neutrons are sub atomic particles. The number of protons and electrons present in an element are equal and termed as atomic number $\left(\text{Z}\right)$. The relation between atomic number, atomic mass and number of neutrons is stated by the formula,

$\text{A}=\text{N}+\text{Z}$

To determine: The missing information from the given table.

Answer to Problem 2.23QP

Solution

The missing information has been rightfully stated.

Explanation of Solution

Explanation

Electrons, protons, and neutrons are sub-atomic particles. The number of protons and electrons present in a neutral element are equal and termed as atomic number $\left(\text{Z}\right)$. The relation between atomic number, atomic mass and number of neutrons is stated by the formula,

$A=N+Z$

Where,

• $A$ is mass number.
• $N$ is number of neutrons.
• $Z$ is atomic number.

(I)

For ${}^{16}\text{O}$,

The given symbol, ${}^{16}\text{O}$, represents that oxygen has $\underset{\_}{16}$ mass number $\left(A\right)$.

The atomic number $\left(Z\right)$ of oxygen is $8$.

Hence, number of protons and electrons is $\underset{\_}{8}$ as it is an uncharged atom.

The number of neutrons is calculated by the formula,

$\begin{array}{l}A=N+Z\\ N=A-Z\end{array}$

Substitute the values of mass number $\left(A\right)$ and atomic number $\left(Z\right)$ in the above expression.

$\begin{array}{c}N=A-Z\\ N=16-8\\ =\underset{\_}{8}\end{array}$

(II)

For number of protons $26$ and neutrons $\left(N=30\right)$.

The number of protons and number of electrons are equal for uncharged atoms.

Hence, the number of electrons is $\underset{\_}{26}$, that is equal to the atomic number $\left(Z\right)$.

This atomic number corresponds to ${}^{56}\text{Fe}$.

The mass number $\left(A\right)$ is calculated by the formula,

$A=N+Z$

Substitute the values of number of neutrons $\left(N\right)$ and atomic number $\left(Z\right)$ in above expression.

$\begin{array}{c}A=N+Z\\ A=30+26\\ =\underset{\_}{56}\end{array}$

(III)

For number of electrons $50$ and mass number $\left(A=118\right)$.

The number of proton and number of electrons are equal for uncharged atoms.

Hence, the number of proton is $\underset{\_}{50}$, that is equal to the atomic number $\left(Z\right)$.

This atomic number corresponds to ${}^{118}\text{Sn}$.

The number of neutrons is calculated by the formula,

$\begin{array}{l}A=N+Z\\ N=A-Z\end{array}$

Substitute the values of mass number $\left(A\right)$ and atomic number $\left(Z\right)$ in the above expression.

$\begin{array}{c}N=A-Z\\ N=118-50\\ =\underset{\_}{68}\end{array}$

(IV)

For number of protons $79$ and mass number $\left(A=197\right)$.

The number of proton and number of electrons are equal for uncharged atoms. Hence, the number of electron is $\underset{\_}{79}$, that is equal to the atomic number $\left(Z\right)$.

This atomic number corresponds to ${}^{197}\text{Au}$.

The number of neutrons is calculated by the formula,

$\begin{array}{l}A=N+Z\\ N=A-Z\end{array}$

Substitute the values of mass number $\left(A\right)$ and atomic number $\left(Z\right)$ in the above expression.

$\begin{array}{c}N=A-Z\\ N=197-79\\ =\underset{\_}{118}\end{array}$

The overall solution of missing information is summarized in Table $2$.

Symbol	${}^{16}\text{O}$	${}^{56}\text{Fe}$	${}^{118}\text{Sn}$	${}^{197}\text{Au}$
Number of Protons	$8$	$26$	$50$	$79$
Number of Neutrons	$8$	$30$	$68$	$118$
Number of electrons	$8$	$26$	$50$	$79$
Mass number	$16$	$56$	$118$	$197$

Table $2$

Conclusion

The given table summarized all the missing information.

Symbol	${}^{16}\text{O}$	${}^{26}\text{Fe}$	${}^{118}\text{Sn}$	${}^{79}\text{Au}$
Number of Protons	$8$	$26$	$50$	$79$
Number of Neutrons	$8$	$30$	$68$	$118$
Number of electrons	$8$	$26$	$50$	$79$
Mass number	$16$	$56$	$118$	$197$