Names, Symbols and Atomic Numbers of Elements
At the end of the 18th century, Lavoisier compiled a list of the 23 elements known at that time; by 1870, 65 were known; by 1925, 88; (Silberberg 2009); Today, there are 118. The elements from atomic numbers 1 through 98 exist in nature, although some are found only in trace amounts and others were synthesized in laboratories before being found in nature. Elements 99 to 118 have only been synthesized in laboratories or nuclear reactors. The synthesis of elements having higher atomic numbers is currently being pursued.
There are 80 elements that have at least one stable isotope and 38 that have exclusively radionuclides, which decay over time into other elements. Numerous synthetic radionuclides of naturally occurring elements have also been produced in laboratories. Beyond the 339 naturally occurring nuclides, more than 3000 radionuclides of varying half-lives have been artificially produced and characterized.