Protons give a positive charge and the amount of the protons is what the atomic number is, which is what the atom is such as iron, irons atomic number is 26 this means it has 26 protons, if there were to be two more protons added to it the whole atom would change into a COMPLETELY different element which would be nickel with the atomic number of 28. Neutrons add mass to the atom and electrons balance the amount of negative and positive charges
Neutrons keep the atom stable