Chapter 4, Problem 23E

Interpretation Introduction

Interpretation:

The table with atomic notations is to be completed by providing the missing information.

Concept introduction:

The atomic number of an atom is equal to the number of protons in an atom. Mass number or atomic mass of an atom can be calculated by taking the sum of atomic number and number of neutrons.

Answer to Problem 23E

The table with atomic notations with complete information is shown below.

Atomic Notation	Atomic Number	Mass Number	Number of protons	Number of neutrons	Number of electrons
${}_5^{11}\text{B}$	$5$	$11$	$5$	$6$	$5$
${}_7^{15}\text{N}$	$7$	$15$	$7$	$8$	$7$
${}_{20}^{40}\text{Ca}$	$20$	$40$	$20$	$20$	$20$
${}_{80}^{200}\text{Hg}$	$80$	$200$	$80$	$120$	$80$

Explanation of Solution

In the atomic notation, ${}_{\text{Z}}^{\text{A}}\text{Sy}$ the ‘Sy’ represents the symbol of the element, the subscript represents the atomic number and the superscript represents the mass number. The atomic number is equal to the number of protons present in the atom. For a neutral atom, the number of electrons is same as the atomic number.

The number of neutrons is calculated by the formula shown below.

$\text{Number}\text{of}\text{neutrons}=\text{Mass}\text{number}-\text{Atomic}\text{number}$ …(1)

The given atomic notation is ${}_5^{11}\text{B}$. The atomic number for the given notation is $5$. Thus, the number of electrons and protons are $5$. The mass number is $11$.

Substitute the values of mass number and atomic number in the equation (1).

$\begin{array}{rll}\text{Number}\text{of}\text{neutrons}& =& 11-5\\ & =& 6\end{array}$

Thus, the number of neutrons in atom of ${}_5^{11}\text{B}$ is $6$.

The given atomic notation is ${}_7^{15}\text{N}$.The atomic number for the given notation is $7$. Thus, the number of electrons and protons are $7$. The mass number is $15$.

Substitute the values of mass number and atomic number in the equation (1).

$\begin{array}{rll}\text{Number}\text{of}\text{neutrons}& =& 15-7\\ & =& 8\end{array}$

Thus, the number of neutrons in atom of ${}_7^{15}\text{N}$ is $8$.

The given atomic notation is ${}_{20}^{40}\text{Ca}$.The atomic number for the given notation is $20$. Thus, the number of electrons and protons are $20$. The mass number is $40$.

Substitute the values of mass number and atomic number in the equation (1).

$\begin{array}{rll}\text{Number}\text{of}\text{neutrons}& =& 40-20\\ & =& 20\end{array}$

Thus, the number of neutrons in atom of ${}_{20}^{40}\text{Ca}$ is $20$.

The given atomic notation is ${}_{80}^{200}\text{Hg}$.The atomic number for the given notation is $80$. Thus, the number of electrons and protons are $80$. The mass number is $200$.

Substitute the values of mass number and atomic number in the equation (1).

$\begin{array}{rll}\text{Number}\text{of}\text{neutrons}& =& 200-80\\ & =& 120\end{array}$

Thus, the number of neutrons in atom of ${}_{80}^{200}\text{Hg}$ is $120$.

The table with the information of atomic number, mass number, number of neutrons, number of protons and number of electrons for given atomic notations is shown below.

Atomic Notation	Atomic Number	Mass Number	Number of protons	Number of neutrons	Number of electrons
${}_5^{11}\text{B}$	$5$	$11$	$5$	$6$	$5$
${}_7^{15}\text{N}$	$7$	$15$	$7$	$8$	$7$
${}_{20}^{40}\text{Ca}$	$20$	$40$	$20$	$20$	$20$
${}_{80}^{200}\text{Hg}$	$80$	$200$	$80$	$120$	$80$

Conclusion

The table with atomic notations with complete information is shown below.

Atomic Notation	Atomic Number	Mass Number	Number of protons	Number of neutrons	Number of electrons
${}_5^{11}\text{B}$	$5$	$11$	$5$	$6$	$5$
${}_7^{15}\text{N}$	$7$	$15$	$7$	$8$	$7$
${}_{20}^{40}\text{Ca}$	$20$	$40$	$20$	$20$	$20$
${}_{80}^{200}\text{Hg}$	$80$	$200$	$80$	$120$	$80$