How does adding one more particle to the nucleus of an atom give that atom new properties? I can see how it changes it's mass, that's obvious... But how does it give that new atom different properties like color?
A good example would be: start with a copper atom (Cu), with the atomic number 29, thus Cu has 29 protons, and you add one proton to the nucleus you are left with an atom of Zinc (Zn) with the atomic number 30, thus 30 protons. The first element mentioned is a totally different color than the second, and conducts electricity better etc.
Not only protons, but neutrons, which are the same type of particle (Baryon) affect the properties of the element in a much different and much less important manner. Adding a neutron only creates an isotope of that element, not a different one all together, unlike adding a proton.
Also, it is obvious that adding (or subtracting) electrons does not make a difference. For example, if you remove 28 electrons (I know that would take huge amounts of energy, but lets ignore that) that "orbit" the copper atom, we are still left with a copper atom, although a ion, but still a copper atom.
So, its apparent that only protons play a major role in "making" elements different from each other. How and why? Also, the same can be asked about the protons themselves and quark flavor.