Question

How is the number of neutrons and in nucleus of an atom calculated

Answer 1

The number of neutrons in an atoms nucleus can be calculated by subtracting the atomic number of that atom from its mass number.

$(mass number - atomic number = number of neutrons)$

Answer 2

Explanation:

Atomic number is defined as the sum of total number of protons present in an atom. Each element has different atomic number.

Whereas mass number is the sum of total number of both protons and neutrons present in an element.

For example, an atom with mass number as 15 and has atomic number 7. Then it means it has 7 protons.

Therefore, number of neutrons present in it will be calculated as follows.

                    Mass number = no. of protons + no. of neutrons

                         15 = 7 + no. of neutrons

                    no. of neutrons = 15 - 7  

                                               = 8

Thus, we can conclude that the number of neutrons is calculated as mass number minus total number of protons present in the atom.