# The electric repulsion of electrons and their attraction

1. Feb 17, 2015

### Quds Akbar

If electrons repel then why are particles attracted to each other so why do particles attract and what is the ratio of the gravitational attraction to the electric repulsion of both an atom and an electron? Thanks!

2. Feb 17, 2015

### ZapperZ

Staff Emeritus
There appears to be a lack of logic in this question, and I don't think this has anything to do with "quantum physics" where it was posted.

1. Yes, electron repels OTHER electron. But why would it puzzle you that electron and proton attract? After all, they have opposite charge to each other. So to answer your question on why they attract, it is because they have OPPOSITE charge, unlike electron and another electron.

2. "electric repulsion of both an atom and an electron"?? What is this and what gave you the idea that a neutral atom and an electron have a repulsion?

3. The calculation of the electrostatic force and gravitational force are not that difficult. Put two electrons at a distance from each other, and then use the Coulomb force to calculate the repulsive force, and the universal law of gravitation to calculate the attractive force.

Zz.

3. Feb 17, 2015

### Quds Akbar

No what I meant is atoms alone and electrons alone. Do atoms repel? That is my question. And I meant by the ratio is the ratio ratio of the gravitational attraction to the electric repulsion of an electron, and the other ratio for atoms if an electric repulsion exists. I am sorry for phrasing that improperly and I hope you now get my point, I will try to do a better job of phrasing statements next time.

4. Feb 17, 2015

### ZapperZ

Staff Emeritus
No. They don't attract either.

I am not sure of where you'd get this. We usually teach students that light charges repel, unlike charges attract, and neutral ones don't do anything. Did you miss these lessons that day?

Note that I am excluding any influences of bonding, including Van de Waals forces, etc., since your question is based entirely on classical E&M issues.

Zz.

5. Feb 17, 2015

### DEvens

Actually, it's a puzzle for grad students studying quantum field theory. Why do like charges repel and unlike attract? They both interact through exchange of a photon. So how can bouncing photons back and forth cause attraction in one case and repulsion in the other?

Think about two guys, each sitting in a row boat, and the boats are sitting on a lake. If they throw a baseball back and forth, it will cause them to get farther apart. Each will have to push the ball in the direction of the other, so getting a back reaction. And each will catch the ball coming from the other, again causing a back reaction. So the naïve expectation from normal experience is, tossing photons back and forth should cause repulsion.

The answer is actually pretty tricky, and arises in the fact that the electric field is a quantum field of virtual particles.

6. Feb 17, 2015

### ZapperZ

Staff Emeritus
Do you think this is the level that the OP is asking about? If you did, I certainly missed it in what has been written.

Zz.

7. Feb 17, 2015

### DEvens

I dunno. My crystal ball is cracked.