Saturday, February 4, 2012

Why are electrons represented as a cloud in high school physics textbooks?

As opposed to chemistry textbooks which usually show them as dots. And why isn't it explained?Why are electrons represented as a cloud in high school physics textbooks?
Electrons exist in a probability cloud. You can never know the electron's exact position or, if you do, the exact velocity. The electron is not an object that moves around like a baseball. The reason chemistry uses static diagrams for electrons (more specifically orbits) is not to reflect the actual physics but rather to make the emergent behavior of atoms with each other under relatively normal circumstances sound. It's like saying I know how an Excel spreadsheet works, because it does the way I want it to and is an easy way of explaining/describing the behavior. But, that doesn't mean you know what's going on underneath the hood, so to speak.
The Electron position varies as a function of temperature inside the Atom.The orbit of the electron interacts with other electrons orbit and other atoms in proximity. Hence not all electron are in the same positon and orbit at the same time. .

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Why are electrons represented as a cloud in high school physics textbooks?
Electron has a probability of being anywhere in space, there is no definite position.

However, we can solve for the probability exactly only for hydrogen, somewhat approximately for helium, but for higher elements it gets complicated.

Now, it has been seen that the dots model does not differ substantially from the electron clouds model (after all Bohr did seem correct for a time being, before Heisenberg came up with his ideas). So for many electron systems, it might not be a bad idea to use dots.



Anyway, usually the probability function is such that it peaks at a certain radius, and then decreases to zero. So it's not a bad approximation to assume that the electron is revolving at that radius.Why are electrons represented as a cloud in high school physics textbooks?
The electron 'cloud' representation replaced the old planetary orbit model sometime ago - since, as has been described, the Heisenberg's Uncertainty principle states that one cannot know both the position AND the velocity of such a particle only one OR the other. Hence the most practical way to represent this is in the form of a cloud where all options are represented. Hope this is of some use.
According to Heisenberg uncertainty principle it's not possible to predict position as well as velocity of any electron simultaneously, we can never pin point a place or position in space where the electron is present, so we assume an electron cloud where electrons maybe present or their probability of being present in diffused form is high.

In chemistry textbooks we assume the particle nature of electron rather than the wave nature to simplify problems.
There are a lot sort of particles.The hit is the same radiation but slowly only.It triods namely to them set the net with U.

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