Why are protons positive. Why are electrons negative? Why do they attract?

[KnowledgeIsPower]

Despite studying chemistry I've never actually been given this information, any explanations/theories that could possibly explain why?

 

[ShawnD]

Are you asking why protons are different from electrons, or are you asking why we decided the electrons were negative instead of positive?

I don't know why the protons would be positive and electrons negative; it's just one of those things you have to accept.
As for why electrons are negative instead of positive, that's just the way it was decided. Would it have made any difference if people decided electrons were positive and protons were negative? Obviously it wouldn't.

Why they attract? The general rule is that everything wants to maintain equilibrium and have the lowest potential difference. If you open the door to your house during winter time, heat doesn't enter your house to make the difference in temperature greater; heat leaves your house to make the difference in temperature 0. Positive and negative are a lot like hot and cold; they are opposite, and they cancel each other. Positive and negative will be attracted to each other so they can have the smallest difference of charge possible.

 

[enigma]

'positive' and 'negative' are nothing more than two arbitrary names given to describe a phenomena. The original naming convention was assigned by Ben Franklin when he was doing some sort of experiment. They just as easily could have been called 'up' and 'down' (which have since been given to quarks to denote certain characteristics), or 'black' and 'white', or 'fish' and 'bird'.

 

[KnowledgeIsPower]

I know what they are and it doesn't matter why they were named like that, but what makes their charges different? What makes one 1, and the other, -1.

 

[arildno]

Well, you could give a limited explanation by regarding protons and electrons from the quark level.
On this level, the explanation of the difference in the electron/proton charge (and, for that matter, the neutron's non-charge) is that electrons and protons are constituted from different sets of quarks (i.e. quarks with different charges)
I believe that the proton is constituted by 2 quarks with 2/3 charge units each, along with one quark that has -1/3 charge unit (2/3+2/3-1/3=1).
The electron, I believe, consists of 3 -1/3-quarks (-1/3-1/3-1/3=-1)
The neutron (2/3-1/3-1/3=0) (I think..)

However, your question can be said to be explained only by pushing back the fundamental fact of nature (that there exist opposite charge types associated with certain particles) onto a deeper level.
Explaining that fact of nature would have to be "explained" by other facts of nature, and so on..

 

[jcsd]

aridlino, you're right about the proton and the neutron, but the electron is not a baryon or indeed any kind of hadron, it's a lepton and therfeore an elementary particle in it's own right (i.e. it's not made up of quarks).

 

[arildno]

Good that a person with real knowledge of elementary particles corrected me on this; I felt the ice cracking beneath my feet when I posted it..

 

[jcsd]

I wouldn't say I had a great knowledge on elemntary particles, I've only gleaned a little technical knowledge in this area, anyway here's a nice list of all the subatomic particles, which includes their classification and quark content:

http://hyperphysics.phy-astr.gsu.edu/hbase/particles/parcon.html

 

[Imparcticle]

proton is constituted by 2 quarks

They are constituted of 3 quarks.

A neutron is constituted of 3 quarks also. Unlike the proton which is contituted of 2 up quarks and 1 down quark, the neutron is composed of 2 down quarks and 1 up quark. Does the sum of up or down quarks determine the electrical charge of a [subatomic] particle?

 

[enigma]

I know what they are and it doesn't matter why they were named like that, but what makes their charges different? What makes one 1, and the other, -1.

Only thing I can think of to explain it is: that's the way the universe is. The particles have a property that attracts and repels based on something which we have arbitrarily defined as a "charge". The "charge" behaves according to certain rules, and it is best described in terms of positive and negative terms.

 

[KnowledgeIsPower]

Only thing I can think of to explain it is: that's the way the universe is. The particles have a property that attracts and repels based on something which we have arbitrarily defined as a "charge". The "charge" behaves according to certain rules, and it is best described in terms of positive and negative terms.

It's difficult to understand what charge is, why is is created and why one type of charge is attracted to another. Of course, you could go on asking the why questions forever..

 

[selfAdjoint]

In order for neutral atoms to exist, the two components, nucleus and shell, have to be of opposite sign. This could happen if the nucleus contained antiprotons and the shell antielectrons, or it could happen the way we actually experience, with protons and electrons. And the reason we have this is that antiparticles appear to be extremely rare in the universe. And that is a BIG puzzle because the particles and antiparticles should have been equally produced in the early universe

 

[Imparcticle]

Do quarks have a negative charge because their spin is opposite to the designated opposite (positive) spin?

 

[Janitor]

I don't know that this adds anything useful to the discussion, but I will note that charge is classified as an extensive variable (meaning its net value is proportional to the quantity of substance in the system, taking signs into account if both types of charge are part of the system). Other examples of extensive variables are energy, volume, and momentum. The other class of physical variable is the intensive type, temperature being the prototypical example.

Charge is also a relativistic invariant. The charge of a particle is independent of its speed relative to the observer.

In electrostatics, the divergence of the electric field intensity is proportional to the electric charge density. In a small region of space where the charge is positive, the lines of electric force can be thought of as pointing away from that region. In a small region where the charge is negative, the lines of electric force can be thought of as pointing toward that region. Since vectors (electric field intensity vectors in the case at hand) pointing in opposite directions are considered the negative of one another, it is consistent that positive and negative signs are applied to the two varieties of charge found in nature.

 

[Janitor]

Also-

There is only one type of carrier of force between electric charges, the photon.

If the universe was such that electric charge came in three varieties instead of two, we couldn't use positive and negative signs. A more complex algebra would be needed. For instance, it might turn out that the charge algebra would be SU(3), in which case there would be eight different types of force carriers instead of one.

Nature does in fact have a type of 'charge' that comes in three and exchanges eight types of bosons: the so-called color charge of chromodynamics.

 

[quartodeciman]

Benjamin Franklin decided there was just one kind of electrical fluid in nature. He opined that wool rubbing wax took electricity away from the wax. The wool ended up with a surplus of electricity and the wax ended up with a deficit of electricity. Therefore, he described the surplus as + and the deficit as -, in analogy to credits and debits of money. This somehow became the usual designation.

The choice became questionable in the nineteenth century. In electrolysis experiments with charged electrodes in beakers of metal salt solutions, metal would deposit on the - electrodes but not on the +. Odd that the deficit electrical part would get more (interesting) activity than the surplus electrical part. This was resolved by Faraday (I think) proposing that metal atoms already have surplus electricity and naturally migrate to the - electrode, being mobile in the solution. He called charged atoms "ions". He found that the quantity of deposited metal could be predicted accurately by current times time.

Later in the nineteenth century, cathode rays were produced and studied assiduously. If the cathode (- terminal) of a cathode ray tube is heated, then cathode rays are produced (a glow occurs). If the anode (+ terminal) is heated instead, this doesn't work. By this time probably nobody cared about which ought to be called + and which ought to be called -. There are cations (+ charged) and there are anions (- charged). The important thing is that the product Q₁Q₂ is positive when the charges are both + or both - (which means a repulsive force) and the product is negative when the charges are +- or -+ (which means an attractive force).

It must have also set people back in their chairs when Rutherford, Geiger and Marsden in 1911 showed the electrical charge distribution within the space of atoms. Almost all of the space is where the - charged electrons dwell*. All of the + charge (and also the main part of the atomic mass) is concentrated into a very tiny part of of the atomic space, what we call the "nucleus".

*A LITTLE CORRECTION: They thought that some electrons were in the nucleus too. The neutron had not been conceived yet.

 

[The Bob]

Well here are some suggestion to answers but it gives more questions...

I am only 15 so what I have to say may not be complicated but it should help. I do apologise for any misspellings and the wrong use of language now.

Now I know about quarks and orbitals so it is back to basics. I know that the 1s orbital level contains one up spin and one down spin electron. Therefore I can safely say that the spin of the subparticles have nothing to do with the charges.

Now it is the norm to say that a proton has a +1 charge and an electron has a -1 charge and neutrons have no charge (0). Each subparticle is made of 3 quarks however I do not know the different combinations that make it so the subparticles have different charges. Logic would say that a proton would have two up quarks and one down quarks and an electron would have one up quark and two down quarks. This leaves the neutron. Does it have three up quarks or three down quarks?

Another point that I believe is need to be stated is the fact that both a proton and a neutron have a mass of 1 and an electron has a mass of 1/1840 but the number of electrons and protons are the same. Therefore the overall charge of all atoms should be positive because there is more positive mass and so more positive charge (like gravity on different masses (on the ground or it will not work the same (LOL))). However atoms are neutral (unless they are ions) so although it makes sense why the charges balance out it does not make sense in terms of mass.

Yet another point. Why doesn't the protons and electrons attract each other? It should be that they do. Look at magnets. The south pole of one magnet and the north pole of another magnet attract each other. It was put down to the 'Colossians Affect'. This was a theory that the subparticle were held apart by another force that scientists could not find. They thought this was too religious and discarded it. It is in the bible though that everything is held by the hand of God and that if he were to release that everything would be in ruins.

The easiest why to answer all of these questions would be that there are antisubparticles (suggested by selfAdjoint), but there is not much proof for any anti-substains (e.g. anti-matter, anti-particles etc.). It is likely to be a that-is-how-the-universe-is question and answer scenario, but if people continue to put up suggestion it might fall into place and I may think of something.

Anyway hope this was useful in some way, even if it is to prove me wrong (as the best way to prove anything is to disprove everything else).

Hope I can be as intelligent as all of you one day.

The Bob (2004 ©)

 

[selfAdjoint]

Up quarks have a charge of +2/3 (positive charge numerically 2/3 of an electron's charge). Down quarks have a charge of -1/3. Proton is 2 ups and a down as you say making 4/3 - 1/3 = 1. Neutron is 2 downs and an up, -2/3 + 2/3 = 0. Notice the the neutron has a magnetic moment - it will turn in a magnetic field - showning that it's components are cherged even if the whole particle isn't.

Protons and electrons do attract each other by opposite electric charge. And protons and protons repel each other by having the same charge. But in both cases there are other things happening that prevent the obvious result of electrons spiraling into the nuclei, which then explode.

First of all note that sidewise motion can frustrate attraction. The moon and the Earth attract each other; why doesn't the moon then fall down on us? In fact the moon is constantly falling, but it also has a sideways speed, so that when it falls to point a it has also moved away from the original line to Earth and its acquired velocity is partly tangential,, and so on around the orbit. Electrons do this too, although they do it quantum fashion. And as for exploding nuclei, they are kept together by the strong force, which has a different kind of charge named color, and which is able to overcome the electrical repulsion.

 

[GCT]

Not to sound rude, however, this question is nonsensical.

What is "negative" and what is "positive" but mere words and symbols. For the most part, science is empirically based as well as experimental. Too many people believe that science itself is largely attributable the intrinsic reasoning ability (bordering on the philosophical) and genius; in reality, it had taken a very long time to reach where we are today, scientifically, mostly since it had taken many trials and errors, experiments, many paradigm shifts. And thus we have such terms as negative and positive, since these are the terms which have proven themselves most useful.

------------
http://groups.msn.com/GeneralChemistryHomework

 

[The Bob]

Cheers

Up quarks have a charge of +2/3 (positive charge numerically 2/3 of an electron's charge). Down quarks have a charge of -1/3. Proton is 2 ups and a down as you say making 4/3 - 1/3 = 1. Neutron is 2 downs and an up, -2/3 + 2/3 = 0. Notice the the neutron has a magnetic moment - it will turn in a magnetic field - showning that it's components are cherged even if the whole particle isn't.

I understand about the protons and the neutrons, now (thanks ), but what about the electons? Having thought about it, logically it should be three down quarks as that would be -1/3 -1/3 -1/3 = -1. Is this right? Does it have three down quarks or is it three up quarks? (Or have I missed the point?) Or is it just something I have to execpt?

Protons and electrons do attract each other by opposite electric charge. And protons and protons repel each other by having the same charge. But in both cases there are other things happening that prevent the obvious result of electrons spiraling into the nuclei, which then explode.

Is this to say that the neutrons hold the protons together so they do not fly out by their repelling charges?

And what about my point on the different mass sizes of the negative and positive subpartilces? Does that not matter to the overall charge then (as it makes sense to me that all atoms should be positive (but I know they are not)).

First of all note that sidewise motion can frustrate attraction. The moon and the Earth attract each other; why doesn't the moon then fall down on us? In fact the moon is constantly falling, but it also has a sideways speed, so that when it falls to point a it has also moved away from the original line to Earth and its acquired velocity is partly tangential,, and so on around the orbit. Electrons do this too, although they do it quantum fashion. And as for exploding nuclei, they are kept together by the strong force, which has a different kind of charge named color, and which is able to overcome the electrical repulsion.

Thanks for this bit. Makes perfect sense and will help me in the future to understand more advanced Chemistry

The Bob (2004 ©)

 

[The Bob]

Not to sound rude, however, this question is nonsensical.

What is "negative" and what is "positive" but mere words and symbols. For the most part, science is empirically based as well as experimental.

Well it is one of those things you have to live with. Why is the colour blue called blue? Why do we pronounce the word why the same as the letter y? It is just the way we are. It is the same for positive and negative. I also like to imagine poistive and negative with numbers that attract or not e.g. -1 and 2 means that the 2 is larger and so it is positive. It doesn't work for everyone but there you go.

Too many people believe that science itself is largely attributable the intrinsic reasoning ability (bordering on the philosophical) and genius; in reality, it had taken a very long time to reach where we are today, scientifically, mostly since it had taken many trials and errors, experiments, many paradigm shifts. And thus we have such terms as negative and positive, since these are the terms which have proven themselves most useful.

I hope we call all learn to use each other to discover more. That is the problem with the scientific world. Everyone wants credit for something, even if it isn't theirs. If we all worked together than maybe these questions would be answered faster. I may not know a lot about the areas of science that some people talk about but if people explained it to me then there would be another person thinking about it and more chance of an answer. I am fairly logical.

Hope we can all learn from each other in a way that will enrich our lifes.

The Bob (2004 ©)

 

[The Bob]

Ok. Anything I have said about electrons having quarks please ignore. I got my science partner to explain it to me and I apologise. I didn't understand. I had not learned about Baryons and Leptons.

The Bob (2004 ©)

 

[mizzuno]

If these particles are attracted to one another, shouldn't electrons be pulled into the nucleus? I gather the reasoning is because of the strong force? If that's the case i need to understand this "strong force" better..

Mizzuno

 

[FZ+]

No. The reason electrons aren't pulled in is because their energies are quantised.

 

[The Bob]

If these particles are attracted to one another, shouldn't electrons be pulled into the nucleus? I gather the reasoning is because of the strong force? If that's the case i need to understand this "strong force" better..

Mizzuno

Sorry to tell you Mizzuno but I have already asked this.

First of all note that sidewise motion can frustrate attraction. The moon and the Earth attract each other; why doesn't the moon then fall down on us? In fact the moon is constantly falling, but it also has a sideways speed, so that when it falls to point a it has also moved away from the original line to Earth and its acquired velocity is partly tangential,, and so on around the orbit. Electrons do this too, although they do it quantum fashion. And as for exploding nuclei, they are kept together by the strong force, which has a different kind of charge named color, and which is able to overcome the electrical repulsion.

I still would like to know, however, if the neutrons hold the protons together so they do not fly out by their repelling charges. Do they?

And what about my point on the different mass sizes of the negative and positive subpartilces? Does that not matter to the overall charge then (as it makes sense to me that all atoms should be positive (but I know they are not)). Different masses must have different sized forces and as an electron is smaller it must have a smaller force apply from it.

Cheers

The Bob (2004 ©)

 

[KnowledgeIsPower]

Just like many questions regarding gravity, it seems difficult to explain exactly why one thing can attract another through thin air.
My entire chemistry education has basically been founded on positive and negative attracting, but i don't really know why they attract.
Just an amusing point.

 

[The Bob]

Just like many questions regarding gravity, it seems difficult to explain exactly why one thing can attract another through thin air.
My entire chemistry education has basically been founded on positive and negative attracting, but i don't really know why they attract.
Just an amusing point.

Can't help then? I would like to know to my post.

The Bob (2004 ©)

 

[The Bob]

I still would like to know, however, if the neutrons hold the protons together so they do not fly out by their repelling charges. Do the neutrons hold the protons together?

The Bob (2004 ©)

 

[KnowledgeIsPower]

I still would like to know, however, if the neutrons hold the protons together so they do not fly out by their repelling charges. Do the neutrons hold the protons together?

The Bob (2004 ©)

Hmm, good question, it seems to be something to do with the neutrons from what I've read on the web but I've struggled to find an exact answer.
If nobody can come up with a reason by tomorrow morning i'll ask my chemistry professor tomorrow afternoon.

 

[loseyourname]

If these particles are attracted to one another, shouldn't electrons be pulled into the nucleus? I gather the reasoning is because of the strong force? If that's the case i need to understand this "strong force" better..

Mizzuno

This question is actually addressed in the Feynman lectures, which are linked to in the physics napster thread in the General Physics forum. The answer is:

What keeps the electrons from simply falling in? [The uncertainty principle]: If they were in the nucleus, we would know their position precisely, which would require them to have a very large, but uncertain, momentum, i.e., a very large kinetic energy. This would cause them to break away from the nucleus. They make a compromise: they leave themselves a little room for this uncertainty and then jiggle with a certain amount of minimum motion in accordance with this rule.

It wasn't really the answer I was expecting. I was previously under the impression that the uncertainty relations were only an expression of our own limitation as subjective observers of a subatomic event, but apparently they are actually an expression of a fundamental principle governing the behavior of small particles. If you're curious, the relation used here is:

$$\Delta x \Delta \rho \geq \frac{h}{2\pi}$$

Where
x = the position of the particle,
$\rho$ = the momentum of the particle, and
h = Planck's constant

 

[The Bob]

If nobody can come up with a reason by tomorrow morning i'll ask my chemistry professor tomorrow afternoon.

Quality. Cheers . And maybe about my other point (about the forces that an electron and a proton apply as an electron is so much smaller).

The Bob (2004 ©)

 

[loseyourname]

Charge is independent of mass.

 

[The Bob]

If nobody can come up with a reason by tomorrow morning i'll ask my chemistry professor tomorrow afternoon.

Quality. Cheers . Maybe you could ask about my other point (about the different mass of the protons and electrons).

And what about my point on the different mass sizes of the negative and positive subpartilces? Does that not matter to the overall charge then (as it makes sense to me that all atoms should be positive (but I know they are not)).

The Bob (2004 ©)

 

[The Bob]

Sorry my computer just caught up.

The Bob (2004 ©)

 

[The Bob]

Charge is independent of mass.

I don't know why but you saying that makes more sense then when it was in my head

Cheers loseyourname

The Bob (2004 ©)