Chapter 1, Problem 1PP

Interpretation Introduction

Interpretation:

The number of protons and neutrons in the isotopes of nitrogen is to be determined.

Concept introduction:

Isotopes are the two or more atoms that have same number of protons but different number of neutrons.

In the periodic table, atomic number is represented by Z. Atomic number is the number of protons present in the nucleus.

Mass number is the sum of number of neurons and number of protons present in the nucleus of the atom. Mass number is represented by A. Mathematically, mass number is calculated as:

$\text{A}=n+p$ …… (1)

Here, A is the atomic mass, $n$ is the number of neutrons, and $p$ is the number of protons.

Answer to Problem 1PP

Solution: ${}^{14}\text{N:}7p\text{and}7n$

${}^{15}\text{N:}7p\text{and}8n$

Explanation of Solution

The atomic number (Z) from the symbol for nitrogen is $7$ .

The number of protons is same as the atomic number. So, the numbers of protons for both the isotopes of nitrogen are 7.

The total number of protons and neutrons is equal to the atomic mass. Therefore, the number of neutrons is calculated as follows:

$\text{A= }n+p$

Rearrange the above equation:

$n=\text{ A}+p$…… (2)

Here, A is the atomic mass of the element.

For ${}^{14}\text{N}$, Substitute 14 for A and 7 for number of protons in the above equation as follows:

$\begin{array}{c}n=14-7\\ =7\end{array}$

For ${}^{15}\text{N}$, Substitute 15 for A and 7 for number of protons in the above equation as follows: $\begin{array}{c}n=15-7\\ =8\end{array}$

Conclusion

For ${}^{14}\text{N}$, number of protons is 7, number of neutrons is 7.

For ${}^{15}\text{N}$, number of protons is 7, number of neutrons is 8.