The Visual Elements Periodic Table - Chemsoc
http://www.rsc.org/chemsoc/visualelements/pages/pertable_j.htm

General Chemistry Online – Fred Senese
http://antoine.frostburg.edu/chem/senese/101/index.shtml

Chemistry in History - Chemical Heritage Foundation
http://www.chemheritage.org/discover/chemistry-in-history/index.aspx

The Wooden Periodic Table Table – Theodore Gray
http://www.theodoregray.com/PeriodicTable/

chemguide – Jim Clark
http://www.chemguide.co.uk/