why is it that two magnets with the same charge repel, but two nucleons in an atom with the same charge do not

Answer 1

The strong nuclear force is an attractive force and much stronger than the replusive electromagnetic force. However, it is only effective at nuclear distances. There is also a limit to the strong nuclear force - if the atom is too large (actually, if the energy of the nucleus is not in a stable configuration), the nucleus splits or otherwise releases excesses energy using the weak nuclear force.

In term of relative strength, the strong nuclear force is much stronger than the weak nuclear force, which is much stronger than the electromagnetic force. However, the strong force only works within the nucleus, and the weak force within the atom, while the EM force is effective over much larger distances.

Now consider this: The electromagnetic force is the weakest of the three, but you can easily pick up an iron nail with a small, hand-held magnet. The collective gravity of the entire Earth is working against the magnet, but the magnet easily picks up the nail. Gravity is infinite in range, which means theoretically an infinite number of particles can contribute to gravity (hence a black hole); but it is 10^35 times weaker, or one hundred million, trillion, trillion, trillion times weaker than electromagnetism. This has lead to some very interesting theories, and the investigation is ongoing (see link).

Answer 2

Whoever said they don't?

The reason all of the protons stay next to each other is twofold.

First, the orbiting electrons are pushing inwards on the protons. Now you would think that after all this pushing and counterpushing that the atoms would fly apart into a million pieces. This WOULD be true....

....if the electrons weren't moving faster than the speed of light. This is proven by how we have never actually "seen" an electron and can only predict their approximate presence by use of differential equations and quantum mechanics (really advanced math and physics) to define electron clouds. Electrons move so fast that light which bounces off of them is too slow to show where they are.

Second is that the neutrons in an atom are equally attracted (or repelled depending on your school of thought) to each proton because neutral charges are attracted to positive and negative ones. Until a non-charged object makes contact with a charged one, it will continue to be attracted. When they do make contact though, the charge disperses and the non-charged object shares the charged objects charge. Problem here is that we don't know is protons and neutrons constantly balance out or change because we don't know if (or how) they actually touch each other in a nucleus.

Answer 3

Magnets have poles not charges. Nucleons within the nucleus or protons do repel each other but they are bound together by the strong force which is much stronger than the electrical force of repulsion but is only effective at nuclear distances and in the presence of neutrons.

Answer 4

they do repel each other. That is why larger atoms requre more neutron to stay together (the neutral particles separate the protons)

Answer 5

think of the negative side as a "ground" and the positive as a source of energy