|MadSci Network: Physics|
The term "electron cloud" is a bit misleading. It is known that it is not possible to determine the position of electrons in atoms and molecules. It is only possible to say that there is a certain "probability" of finding an electron at a given position. If you think of "taking pictures" of the atom or molecule -- lots of them -- you would find the location of the electrons more likely to be in some places than others, but not exactly in the same places. So the collection of the snap shots will be "cloudy". Hence the term "electron cloud." A "cloud" of something means a lot of them close together but not constantly touching each other, usually in the air. You can talk about a rain cloud -- a bunch of water droplets in the air, or a cloud of flies or gnats. Scientists use "cloud of electrons" to describe a loose collection of electrons. Generally, a cloud of electrons only occurs in small chambers in laboratories where scientists study how they react with other things.
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