why electron moves?

why electron moves?


2 Answers

sanjay mathai
18 Points
11 years ago

Awesome question! one would think that because protons are positively charged, and electrons are negatively charged, the two should attract and stick together. The reason that doesnt happen cant even begin to be explained using classical physics. This was one of the key mysteries that were cleared up right away by the invention of quantum mechanics around 1925.

    The picture you often see of electrons as small objects circling a nucleus in well defined "orbits" is actually quite wrong. As we now understand it, the electrons arent really at any one place at any time at all. Instead they exist as a sort of cloud. The cloud can compress to a very small space briefly if you probe it in the right way, but before that it really acts like a spread-out cloud. For example, the electron in a hydrogen atom likes to occupy a spherical volume surrounding the proton. If you think of the proton as the size of a grain of salt, then the electron cloud would have about a ten foot radius. If you probe, youll probably find the electron somewhere in that region.

The weird thing about that cloud is that its spread in space is related to the spread of possible momenta (or velocities) of the electron. So heres the key point, which we wont pretend to explain here. The more squashed in the cloud gets, the more spread-out the range of momenta has to get. Thats called Heisenbergs uncertainty principle. It could quit moving if it spread out more, but that would mean not being as near the nucleus, and having higher potential energy. Big momenta mean big kinetic energies. So the cloud can lower its potential energy by squishing in closer to the nucleus, but when it squishes in too far its kinetic energy goes up more than its potential energy goes down. So it settles at a happy medium, with the lowest possible energy, and that gives the cloud and thus the atom its size.

That basically answers your question, although we admit that the answer sounds strange. There really are very definite mathematical descriptions to go along with those words.

Revanth - -
36 Points
11 years ago

Electrons move/accelerate in different directions because of the forces being acted on them. Opposite charges attract (protons and electrons) and like charges repel (protons and protons or electrons and electrons). Electromagnetic forces between electrons and protons cause them to accelerate.

But if you must think about it using potential/kinetic energy, well, all particles have potential energy right now. Even if theres two electrons a million miles away, they still have the slightest bit of potential energy, because they exert the slightest bit of force on each other. Heck, theres gravitational potential energy between me and you, wherever you may be right now, because there is a gravitational force there--a force that could potentially act over a distance, therefore doing work and giving the system of you and me kinetic energy from the gravitational potential energy.

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