In school, we likely learned that an atom looked like the above model, which is TOTALLY WRONG!  Here’s a more accurate diagram of an (simple) atom:

Electrons don’t orbit the nucleus like the planets orbit the sun. Instead, electrons are found in a “cloud of probability” around the nucleus. Instead of orbiting they exist around the nucleus in a fog. As for their location, they don’t exist in any particular place, instead an electron merely has a certain probability of being in one place versus another. An analogy is the spinning blades of a fan or propeller – similarly electrons appear to occupy all the space around a nucleus. Electrons are considered both particle and wave as they exhibit characteristics of both.

The above diagram is for a simple atom and is known as an “s” orbital.  An orbital is an area of space that an electron is likely to inhabit. More complex atoms have electron probability clouds of varying shapes, like the “p” and “d” orbitals below:

Another crazy point is that the cloud of probability isn’t the only place that the electron(s) can be found as there is a non-zero probability that the electron(s) of an atom can be found anywhere in the universe.