[Moon Boots]

Okay, I see it as completely logical that electrons and protons are found closely together within atoms (due to their opposite charges) but what about neutrons? I don't see whats holding them in the atom, and I'm even more confused about how and why they `fuse` with protons to form the nucleus.


Is it to do with quarks? Or simply gravity?

[RelientKFan7]

"I see it as completely logical that electrons and protons are found closely together within atoms (due to their opposite charges)". You do know that electrons are not found in the nucleus? They are found in orbitals of electron clouds outside the nucleus. If i remember correctly, quarks have something to do with decreasing the repulsive force between the protons, so that they can be near each other in the nucleus. For some reason I do not recall about neutrons... P.S. this is my first year of chemistry, correct me if i am incorrect on anything.

[Moon Boots]

Yeah, I know that electrons are in orbitals, by close together I just meant within the atom. The reason why you haven't heard of them yet is probably because they don't really do anything interesting, except decay in some radioactive elements.

From what I know about neutrons they are completely uncharged (hence the name) and are the heaviest sub atomic particle. Together with protons they make up the nucleus of an atom.

[Fred_space]

Ok basically there are four fundimental forces in nature:
-Gravity
-Electromagnetic (combination of electric and magnetic forces but have been unified in one theory)
-Weak
-Strong

Gravity is the weakest by far but is effective over pretty much infinate (for all intents and purposes) distances so its effects are felt over long distances (like galaxys and star systesm) and with huge differences between masses (like humans and Earth), however the other 3 forces are much much stronger which makes gravity irrelivent on the atomic level. Its just too weak to make a difference.

The strong force is what keeps the nucleus together, it bonds the neutrons and protons together, its also what keeps the quarks together inside the protons and neutrons, kind of like magnets attract each other. If 2 protons or neutrons or both come too close however the force becomes extreamly replusive preventing them from actually merging together. The strong force also looses strength very quickly and wont be felt after a few diameters of a proton or a neutron so is not felt outside the nucleus.

For large atoms lots of neutrons are needed to space the protons apart as the protons positive charge would cause the nucleus break apart.

The electrons are kept in orbit because of something to do with the weak force I believe but I dont actually know anything about that so dont take my word for it, but have you ever wondered why the electrons dont jsut fall into the nucleus?

Hope that helped a bit I probably sounded really partronising (I usually do on forums when explaining stuff) so sorry if I did it wasnt intentional.

[Moon Boots]

Don't apologise, that was a great answer Fred. My question about electrons not crashing into the nucleus was coming up next

I don't think I've ever come across `strong` or `weak` forces. Am I right in assuming that they only effect subatomic particles?

Thanks again, I'm trying to get ahead of the rest of my college for when we do cosmology in physics next year.

[Fred_space]

Yep the strong and weak forces are effective only inside the nucleus.

A good way of thinking about the strong force is imagining it as a kind of spring, with the particles at either end of it. You bring them too close and the spring pushes them apart, you pull them away and the spring trys to pull them together, and if you pull them so far apart (outside the nucleus) the spring effectivly breaks and becomes just a piece of wire not pulling or pushing so having no real effect on them.

Thats a great idea about trying to get ahead, you should find it really helps next year!

[nate95366]

The reason electrons do not "fall" into the nucleus is a question that is best answered by the study of "quantum mechanics" and an understanding of Einstein's equation linking mass to energy.

First, quantum mechanics tells us that electrons are in constant wave-like motion in the atom and that they are most likely to be in the area of space that minimizes their potential energy. These areas of minimum potential energy occur outside of the nucleus, principally because the electron and nucleus do not behave like the planets and the sun (their behaviors are described well enough by "classical" mechanics).

Secondly, since protons and electrons are of opposite charge, if one merges with the other they would create a neutron. If you add the mass of a proton and an electron together, though, you don't get quite the same mass of a neutron. This difference is proportional (through Einstein's E=mc2 equation) to the amount of energy it would take to combine the proton and the electron. The amount of energy it takes is only found in the natural world in/near the cores of very massive stars that are near the end of their "life." The product is called a "neutron" star.

Nate