This is Stephen Lower's General Chemistry sources. There are many up-to-date links to general chemistry tutorials, problems, answers, and disquisitions designed for first-year chemistry students.
Welcome to the ACSWeb from the American Chemical Society. This is the official home page of the American Chemical Society. Registration is requested not not required. Most ACS links will be active without registration. All ACS journals are available here.
The CORRECT (!!) version of the modern Periodic Table: WebElements. Elements through 118 have now been discovered, including #117 just synthesized in 2011
How to tell if your periodic table is the "correct" one Look just below element 39 - yttrium. If 71Lu is there - first element in the d-block - then your table is correct. If 57La is there, or something else, then get a different table: lutetium is a d-block element and lanthanum belongs in the f-block.
Diagonalize a matrix! Note: Because of the way the matrix equations are solved, you have to set x = -(eigenvalue). So just change the signs of the eigenvalues and you'll get the correct x values for the Huckel energies.
Here is an excellent Huckel MO program (Simple Huckel MO or SHMO) with a very intuitive GUI. It trequires the proper Java toolkit to be installed - works best with IE.
This site has graphic images of atomic (hydrogenic) orbitals and homonuclear diatomic MOs. This site, the Orbitron is from Mark Winter's well known Sheffield Univ. Periodic Table site.
The following two sites have excellent symmetry material:
St. Olaf University provides this simple look at the Huckel MO method with a few sample molecules.
Finally, NIST, the National Institute of Standards and Technology has, among other http://www.stolaf.edu/depts/chemistry/courses/toolkits/247/js/huckel/things, an atomic clock down-link that will allow you to keep your computer's clock exact.
ChemWeb: jobs, Beilstein Abstracts, much more.
National Library of Medicine: (PubMed, Medline, Cancerlit)
MSDS: Material Safety Data Sheets - from Sigma-Aldrich
MSDS: more MSDS - from Fisher
MSDS: from the University of Vermont (SIRI)
FDA, U. S. Patent & Trademark Office, Environmental Protection Agency