Try our free, interactive periodic table of the elements. Mouse over an element to view details, click on an element for a full summary.

Elements on the periodic table are arranged in groups according to their electron configuration. All elements in a vertical column have the same number of electrons in their outer energy level. Their distance from the nucleus increases as you go down a...

The Periodic Table is an essential part of the language of chemistry. It has much in common with a thesaurus, providing a guide to similarities and differences among the elements. From the way elements are organized in the Periodic Table, we can...

An element is defined by the number of protons in the nucleus of its atoms, but its chemical reactivity is determined by the number of electrons in its outer shell—a property fundamental to the organization of the periodic table of the elements....

The periodic table is one of the most fundamental tools of chemistry. It summarizes information about each element and reveals how the elements are chemically related to one another. The first widely accepted periodic table was published in 1869 by a...

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...