On the left in the table below is a window with a green dot in it.  The green dot represents the location of a chlorine nucleus (significantly enlarged so that you can see it).  On the right hand side are four pull-down menus from which you can choose an orbital to display.  The electronic configuration of a ground state chlorine is [Ne]3s²3p⁵ (1s²2s²2p⁶3s²3p⁵).  This means that the 4s, 3d and 4p orbitals shown are unoccupied;  thus their extent and energy are somewhat different than would be found for orbitals with electrons in them.   The orbitals appear in the pull-down menus from lowest (at top) to highest (at bottom) energy.
    These orbital images are based on calculations done using the GAMESS¹ ab initio quantum mechanics package and MacMolPlt 5.6.²  These orbitals are generated from the GAMESS .log file of a single point energy calculation on a ground state Cl at the 6-311G++(2d,p) level of theory.

Some recommendations on using the viewer:  1) By default the orbital surfaces are displayed as solid.  When looking at more than one orbital simultaneously it is usually better to switch to the mesh display so that you can see through the intersecting surfaces.  2) Zoom in and out.  These orbitals vary greatly in size.

Other web sites with nice orbital pictures: Mark Winter's Orbitron site from Sheffield University in England has very pretty pictures.

Orbital 1: Surface Type: Surface Color: Orbital 2: Surface Type: Surface Color: Orbital 3: Surface Type: Surface Color: Orbital 4: Surface Type: Surface Color: Javascript generated by a perl script (orbtohtml.pl) on Wed May 17 16:27:06 2006. Original page composed by J. Gutow 4/2006.

Instructions for using Jmol to display orbitals: Choose which orbitals to display by selecting them the orbital popup menus.  You can control orbital color and fill mode by selecting the appropriate options following each orbital menu.  ROTATE the image by holding down the mouse button while moving the cursor over the image.  ZOOM by holding down the shift key while moving the cursor up (decrease magnification) or down (increase magnification) on top of the image.  Other options available in the control menu accessible by holding the mouse button down while the cursor is over "Jmol" in the lower right corner (right click also works on a multibutton mouse).  For more info about Jmol go to www.jmol.org.

1. M.W.Schmidt, K.K.Baldridge, J.A.Boatz, S.T.Elbert, M.S.Gordon, J.H.Jensen, S.Koseki, N.Matsunaga, K.A.Nguyen, S.Su, T.L.Windus, M.Dupuis, J.A.Montgomery J. Comput. Chem., 14, 1347-1363(1993).
2. Bode, B. M. and Gordon, M. S. J. Mol. Graphics Mod., 16, 1998, 133-138.