Editing Chemical element (section)

=== Periodic table ===
{{Main|Periodic table}}
{{Periodic table}}

The properties of the elements are often summarized using the periodic table, which powerfully and elegantly organizes the elements by increasing atomic number into rows ([[period (periodic table)|"periods"]]) in which the columns ([[group (periodic table)|"groups"]]) share recurring ("periodic") physical and chemical properties. The table contains 118 confirmed elements as of 2021.

Though earlier precursors to this presentation exist, its invention is generally credited to Russian chemist [[Dmitri Mendeleev]] in 1869, who intended the table to illustrate recurring 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.

Use of the periodic table is now ubiquitous in 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]], [[geology]], [[biology]], [[materials science]], [[engineering]], [[agriculture]], [[medicine]], [[nutrition]], [[environmental health]], and [[astronomy]]. Its principles are especially important in [[chemical engineering]].