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Why are protons positive. Why are electrons negative? Why do they attract? 
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#37
Jun2904, 02:48 PM

Emeritus
PF Gold
P: 3,634

Planck's constant is [itex]6.626~\textrm{x}~10^34 J \cdot s[/itex].
If you rework the relation shown, you can get [tex]\Delta \rho \geq \frac{h}{2\pi \Delta x}[/tex] If the electron's position is known with near certainty (which would be the case if it were to collapse into the nucleus), then [itex]\Delta x[/itex] approaches 0. So let us take the limit of the relation as [itex]\Delta x \rightarrow 0[/itex]: [tex]\Delta \rho \geq \lim_{\Delta x \rightarrow 0}\frac{h}{2\pi \Delta x}[/tex] We can see that [tex]\lim_{\Delta x \rightarrow 0}\frac{h}{2\pi \Delta x} = \infty[/tex] It should be clear that not only can [itex]\Delta \rho[/itex] not be greater than or equal to [itex]\infty[/itex], but it cannot even approach this value if [itex]\Delta x[/itex] approaches 0. Stated simply, the momentum of a particle cannot be close to infinity if its motion is nearly zero. Because of this, the electron must remain somewhere in the electron cloud surrounding the nucleus. 


#38
Jun2904, 04:02 PM

P: 1,954

Neutrons holding protons? Sort of, yes. Within the hadrons, the quarks are held together by the strong force, which is mediated by particles called gluons. (The theory behind this is Quantum Chromodynamics, which is still kinda sketchy.) Some of this force leaks out, and this is what holds the neutrons and protons together. Essentially. 


#39
Jun2904, 04:37 PM

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The Bob (2004 ©) 


#40
Jun3004, 11:29 AM

P: 90

The answer was that nobody knows the real reason at the minute, though it seems to be something to do with binding energy, which is created when protons and electrons combine to form a neutron.
My personal theory is that as protons and electrons combine, neutrons are polar. As there are usually more neutrons in an atom than protons they are arranged much like hydrogen bonds between water molecules, in that like charges from the negative ends of neutrons will attract protons. If there is a greater number of neutrons surely they will hold the protons in the center in a kind of lattice, if arranged correctly. If anyone here has anything to add, or any possible problems with that theory i'd be interested to hear it. But that's just my idea, it's not concrete and i certainly haven't done any experiments to 'prove' it. 


#41
Jun3004, 11:51 AM

P: 1,116

Can't really fault it properly but it is good. The Bob (2004 ©) 


#42
Jun3004, 12:28 PM

P: 90

Perhaps also neutrons are situated evenly at intervals on the 'outside' of a centralised complex of proton/neutrons. If they were situated at regular intervals then surely repullsion away from the neutrons could be the same for all the sides on the protons and they would be repelled towards the center, possibly negating the repullsion they would exert on each other. 


#43
Jun3004, 12:32 PM

Sci Advisor
P: 1,082

The plain fact is, sad to say, nobody has a clue about the fundamentals of electric charge, nor mass  that is, we do not know why charges are either + or  Ne, or + or  e/3, where e is the electron's charge and N is an integer, nor do we know the why of the electric/ magnetic forces. But given the usual assumptions, we can do wonders in explaining chemistry, radar, atomic spectra, superconductivity, and so on. The same goes for masses  although the standard theory does give some clues.
In his great work on Hydrogen, Bohr said: "If, the electron is confined to various discrete, STABLE orbits, then, ....". He subsequently derived the formulas for the spectra of hydrogen. Why stable orbits? Who really knows? But, the mature quantum theory of atomic systems based on the Schrodinger eq. yields Bohr's stable atomic orbits, which we now call stationary states. Why does QM work? Who knows? But, indeed, QM does work  some have called QM the most tested of scientific theories. The end of science is nowhere in sight. Regards, Reilly Atkinson (The KaluzaKlein 5dimensional relativity, the mother of "folded dimensions", does predict quantized charge, but the details don't match reality." 


#44
Jun3004, 02:58 PM

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#45
Jul104, 01:42 AM

P: 15

Proton is positive beaucouse the first subatomic particle that was discovered is positivly charged, and that particle was named proton. It name comes from latin word PROTOS which means the first and the most important. When other particles were discovered they were given names that suite them the most. Electron was given name on Greek language ELEKTRONION which is a kind of rock. It was taken that sign of proton was +1 and of electron 1.



#46
Jul104, 02:07 PM

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#47
Jul104, 04:18 PM

P: 1,116

The Bob (2004 ©) 


#49
Jul204, 02:44 PM

P: 1,116

The Bob (2004 ©) 


#50
Apr209, 09:22 PM

P: 1

Well I came across this forum while studying electricity for my Aviation Maintenance classes and would like to put in my 2 cents:
Quatro.., is right: When Benjamin Franklin made his conjecture regarding the direction of charge flow (from the smooth wax to the rough wool), he set a precedent for electrical notation that exists to this day, despite the fact that we know electrons are the constituent units of charge, and that they are displaced from the wool to the wax  not from the wax to the wool  when those two substances are rubbed together. This is why electrons are said to have a negative charge: because Franklin assumed electric charge moved in the opposite direction that it actually does, and so objects he called "negative" (representing a deficiency of charge) actually have a surplus of electrons. By the time the true direction of electron flow was discovered, the nomenclature of "positive" and "negative" had already been so well established in the scientific community that no effort was made to change it, although calling electrons "positive" would make more sense in referring to "excess" charge. You see, the terms "positive" and "negative" are human inventions, and as such have no absolute meaning beyond our own conventions of language and scientific description. Franklin could have just as easily referred to a surplus of charge as "black" and a deficiency as "white," in which case scientists would speak of electrons having a "white" charge (assuming the same incorrect conjecture of charge position between wax and wool). However, because we tend to associate the word "positive" with "surplus" and "negative" with "deficiency," the standard label for electron charge does seem backward. Because of this, many engineers decided to retain the old concept of electricity with "positive" referring to a surplus of charge, and label charge flow (current) accordingly. This became known as conventional flow notation. FUNNY how those kind of things happen. Source : http://www.allaboutcircuits.com/vol_1/chpt_1/7.html Talk about bringing back a dead post hahaha 


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