Discover the history, structure, and importance of the periodic table of elements, from Mendeleev’s discovery to modern scientific applications.

Is It Time to Upend the Periodic Table? The iconic chart of elements has served chemistry well for 150 years. But it’s not the only option out there, and scientists are pushing its limits.

Charles Janet’s left-step table. Wikipedia, CC BY-SA Settling on a design The modern table is actually a direct evolution of Janet’s version. The alkali metals (the group topped by lithium) and the ...

The orderly periodic table—often printed with just the chemical symbol and atomic weight of its 118 elements—doesn't quite manage to convey to nonscientists the richness of what these substances bring ...

The periodic table of elements, devised by Russian chemist Dmitri Mendeleev, is a two-dimensional array of the chemical elements, ordered by atomic number and arranged 18 across by orbitals.

The Group 1 elements are called the alkali metals. They include lithium, sodium and potassium, and are placed in the first vertical column on the left of the periodic table.

Eric Scerri, a UCLA chemistry lecturer, has written at least six books discussing the orientation of the periodic table. His office is cluttered with posters and three-dimensional models of ...

The alkali metals (the group topped by lithium) and the alkaline earth metals (topped by beryllium) got shifted from far right to the far left to create a very wide looking (long form) periodic table.

Groups in the periodic table show patterns in their physical properties and reactivity. These patterns can be used to predict the behaviour of other elements in a group.