Francium, formerly known as eka-caesium and actinium K, is a chemical element that has the symbol Fr and atomic number 87. It has the lowest known electronegativity and is the second rarest naturally occurring element (after Astatine). Francium is a highly radioactive metal that decays into astatine, radium, and radon. As an alkali metal, it has one valence electron.
Marguerite Perey discovered francium in 1939. Francium was the last element discovered in nature, rather than synthesized. Outside the laboratory, francium is extremely rare, with trace amounts found in uranium and thorium ores, where the isotope francium-223 is continually formed and continually decays. Perhaps an ounce exists at any given time throughout the Earth's crust; the other isotopes are entirely synthetic. The largest amount ever collected of any isotope was a cluster of 10,000 atoms (of francium-210) created as an ultracold gas at Stony Brook in 1996.
Wikipedia:WikiProject Chemicals/Data is a collection of links and references that are useful for chemistry-related works. This includes free online chemical databases, publications, patents, computer programs, and various tools.
Science is Fun University of Wisconsin–Madison Chemistry Professor Bassam Z. Shakhashiri, shares the fun of science.
unit-conversion.info A good place to figure out what equals what.
General Chemistry Online Clear text and comprehensive coverage of general chemistry topics by Fred Senese, Dept. of Chemistry Frostburg State University
General Chemistry Demonstration at Purdue Video clips (and descriptions) of lecture demonstrations.
Intota Chemistry Experts A large online listing of real-world chemistry expert biographies provides examples of the many areas of expertise and careers in chemistry.
Chemistry Webercises Directory A large listing of chemistry resources maintained by Steven Murov, Emeritus Chemistry Professor Modesto Junior College.
MathMol MathMol (Mathematics and Molecules) is a good starting point for those interested in the field of molecular modeling.
Chemistry Educational Resources and Essential References from Wiley, the world's largest chemistry publisher
ABC-Chemistry A directory of free full-text journals in chemistry, biochemistry and related subjects.
The Element Song A goofy little song about all of the elements.