This is a large version of the periodic table
and contains the symbol, atomic number, and mean atomic mass
value for the natural isotopic composition of each element. The periodic table of the chemical elements
is a tabular
method of displaying the chemical elements
. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev
in 1869. Mendeleev intended the table to illustrate recurring ("periodic") trends in the properties of the elements. The layout of the table has been refined and extended over time, as new elements have been discovered, and new theoretical models have been developed to explain chemical behavior.
The periodic table is now ubiquitous within the academic discipline of chemistry, providing an extremely useful framework to classify, systematize and compare all the many different forms of chemical behavior. The table has also found wide application in physics, biology, engineering, and industry. The current standard table contains 117 confirmed elements as of 2008-01-27 (while element 118 has been synthesized, element 117 has not).
† A value in brackets, such as [259.101], is the 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 (where necessary) includes its uncertainty in parenthesis. For example, the value of 200.59(2) for mercury means that a normal terrestrial isotopic composition of mercury has a relative atomic mass of 200.59 atomic mass units (u) with an uncertainty of 0.02u, reflecting primarily local variability around the earth.
|| From decay