Question

The nitrogen$\text{-14}$ isotope has a mass number of $\text{14}$ and an atomic number of $\text{7}$. How many neutrons does it have?

Answer 1

Hint: Analyze the given data and terms given in the question. The atomic number that is the number of protons always indicates the number of electrons present in an element. One can calculate the number of neutrons based on the mass number and number of protons.

Complete step by step answer:
1) First of all we will analyze the data given in the question itself. The mass number of nitrogen isotope is given which is fourteen and the atomic number that is the number of the proton is given which is seven.
2) Now as we know an element consists of three terms such as protons, neutrons, and electrons. The protons denote the atomic number of an element and electrons denote the valency of an element. The number of protons is always equal to the number of electrons.
3) The number of electrons varies according to the isotope of that element. The mass number is always the addition of the number of protons and the number of neutrons.
4) Now let us calculate the number of neutrons for the nitrogen$\text{-14}$ isotope as below,
Number of protons $\text{=7}$
Mass number $\text{=14}$
Number of neutrons $\text{=?}$
$\text{Number of neutrons = Mass number - Number of protons}$
Now let us put the values in the above equation we get,
$\text{Number of neutrons = 14 - 7}$
By doing the subtraction we get,
$\text{Number of neutrons = 7}$
Therefore, the nitrogen$\text{-14}$ isotope has $\text{7}$(seven) number of neutrons.

Note:
The isotopes of an element have the same number of protons but the different mass number that is the different number of neutrons. The nitrogen element has three isotopes such as nitrogen$\text{-13}$, nitrogen$\text{-14}$ , and nitrogen$\text{-15}$ which have the number of neutrons as $\text{6, 7, 8}$ respectively.