Hydrogen has an Atomic Number of 1. An atom must possess 1 proton to be called a hydrogen atom. If an atom contains 2 protons, it won’t be hydrogen anymore, but instead helium. An atom without 1 proton is not hydrogen.
To be neutrally charged, the amount of electrons must equal the number of protons in an atom. The number of electrons must also be equal to 1.
Depending on the isotope, however, the number and type of neutrons may vary. An isotope is a particular type of hydrogen. You can have hydrogen-1 which has 0 neutrons. Hydrogen-2 would contain 1 neutron, while hydrogen-3 would have two neutrons.
It is easy to determine the number neutrons present in an atom by looking at its atomic mass, and subtracting the number protons. If your atom has anatomic mass of 3 and you know there is only one proton, you can subtract 1 from 3, which will give you 2. This will tell you that there are 2 neutrons. This is because protons as well as neutrons have approximately 1 amu each. However, electrons are very small and don’t often affect many calculations.