How are the number of protons, electrons and neutrons calculated?

Calculation of number of proton:

1. The protons are positively charged particles present in the nucleus of an atom.
2. The number of proton in an atom is equal to the atomic number of that element.
3. Thus, Number of protons$=$Atomic number $\left(\mathrm{Z}\right)$

Calculation of number of electron:

1. The electrons are negatively charged particles that revolve in the shells around the nucleus.
2. The number of electron in a neutral atom is equal to the atomic number of that element.
3. Thus, Number of electrons in a neutral atom$=$Atomic number $\left(\mathrm{Z}\right)$

Calculation of number of neutron:

1. The neutrons are electrically neutral particles present in the nucleus of an atom.
2. The mass number is the sum of the number of protons and number of neutrons of the element.
3. Thus, the number of neutrons can be calculated from the mass number of the element.
4. Thus, Number of neutrons$=$Mass number $\left(\mathrm{A}\right)$$-$Atomic number $\left(\mathrm{Z}\right)$

Example: Carbon $\mathbf{\left(}\mathbf{C}\mathbf{\right)}$ atom:

The atomic number of Carbon is $6$.

Thus,

Number of protons$=$Number of electrons$=6$

The mass number of Carbon is $12$.

Thus,

Number of neutrons$=12-6=6$

Thus, the number of protons, electrons and neutrons in a Carbon atom are $6$, $6$ and $6$ respectively.