All models of the atom you have ever seen are wrong...

So if you know anything about how atoms are actually put together, you know that every model you have ever seen of an atom is wrong. The electrons are too big, too close to the nucleus and usually too planetary-orbit-like. This clip from Nova Science does an excellent job of showing (and fixing) these problems, as well as a few I hadn't thought of before.

http://www.youtube.com/watch?v=5fPOCcj7gEU

In reality the real reason the models are wrong is that there isn't any way to make an accurate model that is of a size and scale that people could actually see and use. That's part of the problem with atoms after all, they are very small and very hard to wrap our brains around.