This large version of the periodic table contains the symbol, name, atomic number, and standard atomic weight of each element. The key below explains the color-coding and layout of each entry.
atomic mass of the most stable isotope unless it is an integer, in which case it is the mass number of the most stable isotope. In all other cases, the value is the relative atomic mass of common terrestrial composition, according to Atomic Weights of the Elements 2001, and includes its uncertainty in parenthesis. For example, the value of 1.00794(7) for hydrogen means that a normal terrestrial isotopic composition of hydrogen has a relative atomic mass of 1.00794 atomic mass units (u) with an uncertainty of 0.00007u, reflecting primarily local variability around the earth.
‡ This atomic mass is only an estimate, as this element has not yet been discovered.