Periodic Table of the Elements [Basic data, includes printable version] Information on each of the chemical elements and data on their properties. Some site information is only in Czech language. http://www.tabulka.cz/english/

WebElements [Very comprehensive, includes very detailed write ups, basic nuclide data, extensive graphics] Professional scientists and students at school will all find something useful. Includes thousands of images relating to periodicity and structure. http://www.webelements.com/

A Periodic Table of the Elements at Los Alamos National Laboratory [Very basic data, detailed write-ups] The Chemical Science and Technology division's Periodic Table describes the history, properties, resources, uses, isotopes, forms, costs, and other information for each element. http://pearl1.lanl.gov/periodic/

PTE Periodic Table of the Elements [Very basic data, includes writeups, Requires Javascript] http://pte.8k.com

Visual Elements [Detailed data, write-ups, basic listing of nuclides] The Royal Society of Chemistry's (in the UK) contribution to chemistry on the web. http://www.chemsoc.org/viselements/pages/periodic_table.html

X-Ray Properties of the Elements [X-ray properties only] X-ray properties of most of the elements. http://www.csrri.iit.edu/periodic-table.html

Exploring the Table of Isotopes [Nuclide data only, extensive listing of nuclides] Provides isotope data for almost all known nuclides. From Berkeley Laboratory. http://ie.lbl.gov/education/isotopes.htm

ChemicalElements.com: Online Periodic Table [Basic data, limited write-ups] Provides information on the 109 named elements plus elements 110 - 112. http://www.chemicalelements.com

The Periodic Table Challenge [No element data] An auto-scored blank periodic table. The user fills it in online and the score is returned automatically. http://www.ilpi.com/genchem/periodicquiz.html

The Periodic Table of Elements by Kostas Tsigaridis [Detailed data, basic nuclides, limited write-ups, requires Javascript] A Javascript based periodic table. http://atlas.chemistry.uch.gr/ptoe/

Printable Periodic Table [Very basic data, requires Adobe Acrobat Reader] PDF of the Periodic Table arranged in different formats. Files only contain elements' symbols, names and atomic number. http://science.widener.edu/~svanbram/ptable.html

EnvironmentalChemistry.com: Periodic Table of Elements [Very comprehensive data, write-ups, extensive listing of nuclides] Data on elements includes scores of properties, element names in a dozen languages and almost all known nuclides. Environmental chemistry articles round out site. http://EnvironmentalChemistry.com/yogi/periodic/

Periodic Table of the Elements [Very basic data] Includes printable version. http://www.dayah.com/periodic/

Periodic Table of the Elements - ChemGlobe [Detailed data, includes write-ups, basic nuclide data, printable version] Chemical elements database from ChemGlobe. http://www.vcs.ethz.ch/chemglobe/ptoe/

Chemicool Periodic Table [Detailed information on each element, no write-ups] http://www.chemicool.com/

Fast Periodic Table [Basic data] Interactive periodic table. Including uses and discovery. http://www.schoolscience.co.uk/periodictable.html

On-line The Periodic Table of Elements [Basic data, requires JavaScript] Includes historical information about the elements in Italian, but the table itself is in English. http://www.themeter.net/elemen_e.htm

Interactive Periodic Table and Data tables [Very basic data, requires Javascript] Interactive table with pictures of the elements. http://le-village.ifrance.com/okapi/periodic3.htm

David's Whizzy Periodic Table Applet-based table with visualizations of the electron shell model, the nucleus, the visual emission spectrum, and energy levels of the electrons. Also has interesting facts about each element represented. http://www.colorado.edu/physics/2000/applets/a2.html

Printable Periodic Table [Very basic data] Minimalist table that provides symbols, atomic numbers, and atomic weight with four significant figures. http://www.swansontec.com/selement.htm