A $ {}_{86}^{222}Rn{{ }} $ is an Isotope of noble gases radon. How many protons, Neutrons, and electrons are there in one atom of this radon isotope.

Hint: Isotopes are a species of atoms of an element with different atomic masses but the same atomic number and position in the periodic table with similar chemical properties. Isotopes are created due to the change in neutrons.

Complete step by step answer
Any element is generally represented as ${}_Z^AX$. $X$ is the symbol of atom/element, $A$ denotes the atomic mass of an atom, and $Z$ denotes the atomic number of the atom.
The atomic number of an atom is equal to the number of protons present in it, which is always equal to the no of electrons in it.
Protons and Neutrons are always present in the nucleus of an atom while electrons are always revolving around the nucleus. The atomic mass of an atom is composed of its Nucleus and the mass of electrons is neglected.
So in isotopes, the change in atomic masses arises due to the change in the number of Neutrons in different isotopes as the atomic mass of an atom is given as the sum of the number of protons and neutrons present in the nucleus of that atom.
In the given $ Rn $ isotope, the atomic no is $ 86 $ , which means the no protons and electrons present in the atom is also equal to $ 86 $
Given atomic mass is $ \;222 $ , the atomic mass is given as;
 $\text{ Atomic mass} = \text{No of protons} + \text{no of neutrons }$
Now we will calculate the number of neutrons in the radon isotope. They will be;
 $ \text{No of neutrons}$ = $\text{ Atomic mass-no of protons} $
No of neutrons $ = $ $ \;\;222\, - \,86 $
No of neutrons $ = $ $ 136 $
Hence the no of Protons, Neutrons, and electrons in $ {}_{86}^{222}Rn{{ }} $ isotope are $ 86 $ , $ 136 $ and $86$ respectively.

Note:
An atom consists of three subatomic particles electrons, protons, and neutrons. Electrons are the negatively charged particles, protons are the positively charged particles and Neutrons are charge-neutral particles.