Protons and neutrons are located in the nucleus of the atom while the electrons move in the trajectory of the shell
<h3>Further explanation
</h3>
Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.
So Isotopes are elements that have the same Atomic Number (Proton)
Isotopes of Helium : helium-3 and helium-4
protons = 2
electrons=protons=2
neutron=mass number-atomic number=3-2=1
protons = 2
electrons=protons=2
neutron=mass number-atomic number=3-2=1
protons = 2
electrons=protons=2
neutron=mass number-atomic number=4-2=2
Protons and neutron in the nucleus, electrons in the shell