Àdàkọ:DMCÀdàkọ:Merge partner A table of chemical elements ordered by atomic number and color coded according to type of element. Given is each element's name, element symbol, group and period, Chemical series, and atomic mass (or most stable isotope). Some element categories in the periodic table Some element categories in the periodic table The isotopic composition of this element varies in some geological specimens, and the variation may exceed the uncertainty stated in the table. The isotopic composition of the element can vary in commercial materials, which can cause the atomic weight to deviate significantly from the given value. The isotopic composition varies in terrestrial material such that a more precise atomic weight can not be given. The atomic weight of commercial lithium can vary between 6.939 and 6.996—analysis of the specific material is necessary to find a more accurate value. The element does not have any stable nuclides, and a value in brackets, e.g. [209], indicates the mass number of the longest-lived isotope of the element or characteristic isotopic composition. M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)".