History of the periodic table managed to get thallium, lead, mercury and platinum into the right groups, which is something that Mendeleev failed to do at his first attempt. Odling failed to achieve recognition, however, since it is suspected that he, as Secretary of the Chemical Society of London, was instrumental in discrediting Newlands' earlier work on the periodic table. By 1912 almost 50 different radioactive elements had been found, too many for the periodic table. Frederick Soddy in 1913 found that although they emitted different radiation, many elements were alike in their chemical characteristics so shared the same place on the table. They became
Extended periodic table (detailed cells) Extended periodic table (detailed cells) This is a large version of the extended periodic table of the chemical elements. For the natural isotopic composition of each element it shows "name", "atomic number", "symbol", "standard atomic weight" (or atomic weight) and a link to the element's isotopes. It also has, by keyed markings, a notification of "occurrence", "state of matter" and "metallic character". It is named "extended" because it shows elements that are theoretical only (in period 8), and "large" means that the table might exceed page width. The presentation is wide which means that there are no table parts separated