The three subatomic particles are proton, neutron and electron. Proton and neutron are present inside the nucleus where as the electrons are present revolving in the orbits around the nucleus. Isotopes of the same element have same atomic number but different number of neutrons. Similarly, ions of an element have different number of electrons. For example, neutral Ag atom has 47 electrons, where as [tex]Ag^{+}[/tex]ion has 46 electrons. Atomic number which is the number of protons is unique for an element. So the number of protons would remain same for different atoms of same element Ag.
