The periodic table of the chemical elements (also periodic table of the elements or just the periodic table) is a tabular display of the chemical elements. Although precursors to this table exist, its invention is generally credited to Russian chemist Dmitri Mendeleev
in 1869, who 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 a useful framework to classify, systematize, and compare all
of the many different forms of chemical behavior. The table has found
many applications in chemistry, physics, biology, and engineering, especially chemical engineering. The current standard table contains 118 elements to date. (elements 1â€“118).