Atomic Orbitals
-s orbital
-p orbitals
-d orbitals (Look at all 5 d orbitals)
-f orbital
As shown on the atomic models ( Atom I and Atom II), electrons are normally pictured as moving in circular or elliptical orbits around the nucleus. This is a useful model, which can be used to explain various properties (for instance shells and the octet rule). However, electrons don't move in such well defined trajectories. According to quantum mechanics, the most accurate picture is to define orbitals, as regions of probabilities of finding electrons.
Orbitals are the regions where electrons are most likely to be found when they are bound to a nucleus, so that they are part of an atom. Depending on their energy, they can assume various shapes (as seen below). Those images are obtained based on the solutions of the Schroedinger equation for the hydrogen atom.
© Ricardo Esplugas. All images in this site can be bought in an enlarged version. Please contact me on ricardochemistry@gmail.com