Answer:
Every atom of a given element has the same number of protons
The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force.
Step-by-step explanation:
Atoms are composed of electrons, protons and neutrons. The electron is negatively charged, protons are positively charged and the neutrons have no charge.
Electrons are found in shells while protons are found inside the atomic nucleus. Similar to electrostatic forces between electron and proton, protons of helium are held together by a strong nuclear blinding force.
Note that, all isotopes must have the same atomic number. This shows that they are all the same atom changed by differences in number of neutrons.