Electrons in atoms occupy orbitals. An orbital can be visualized as the volume in which the electron stays as it moves about the nucleus.
Examine the shapes of the atomic orbitals in the n = 1, 2, and 3 shells by clicking the red arrows.
In the image that appears for each orbital, the image on the left shows the surface inside which the electron is principally found. The image on the right is a cross section of how likely it is to find the electron in a particular location. The top right shows a graph of the likelihood of finding the electron as a function of distance from the nucleus.