# B Electrons of atoms

1. Aug 3, 2016

### shina

Electrons moving at descrete orbits or shells ever collide or not. And what will happen if they collide with each other?

2. Aug 3, 2016

### t3rm1

Electrons repel each other. Can not collide.

3. Aug 3, 2016

### t3rm1

...and Pauli exclusion principle say that the electrons can not have same value of quantum numbers.
They can not be near each other

4. Aug 3, 2016

### Staff: Mentor

Depends what you mean by collide. Particles that repel each other can scatter off one-another, which is what must physicists would consider a collision.

They can if they have opposite spin. Indeed, in certain electronic states there is an increase in the probability that two electrons will occupy the same position. Look up Fermi heap.

5. Aug 3, 2016

### Staff: Mentor

They don't move in the classical sense, like planets orbiting a star. They are in stationary states that are fully dependent on the other electrons being present. See also my post above.

6. Aug 3, 2016

### t3rm1

The different spin is different quantum number.
This is that I wrote

7. Aug 3, 2016

### Staff: Mentor

You wrote that the fact that they have different quantum numbers means that "they can not be near each other," but they can have the same set of quantum numbers apart from spin, meaning that they have the same spatial wave function. I don't see therefore how this can lead to saying that they can't be near each other.

8. Aug 3, 2016

Staff Emeritus
t3rm1 is not helping.

In atomic physics, we model the electrons as point particles. Point particles have a zero probability of colliding. These models match the data to our ability to measure. Certainly electrons feel each other's electric field.

9. Aug 3, 2016

### Khashishi

A collision in quantum mechanics refers to a scenario where you start with various particles moving in, there is some interaction, and you have various particles moving out. It's not something that involves two particles touching, and it's not something that happens at any particular time or place. Basically, we can look at the before and after pictures of two or more particles which come near each other and decide, was there a collision? For example, consider the following scenario: Before, we have a hydrogen atom in the 1s state and an electron. After, we have a hydrogen atom in the 2p state and an electron. We can conclude that the electron has collided with the atom and given it some energy.

With this in mind, there is no way to make sense of your question. You can have spontaneous processes like auto-ionization within a multi-electron atom. But I don't think that's what you had in mind.