Periodentafel

Periodentafel, in German, refers to the periodic table of elements. The Periodentafel is a tabular arrangement of chemical elements organized by increasing atomic number, electron configuration, and recurring chemical properties. It provides a framework for predicting elements’ behavior and tracking trends across the elements.

The modern periodic table emerged from the work of Dmitri Mendeleev in 1869, who arranged elements by atomic weight and properties, leaving gaps for undiscovered elements and predicting their properties. Later, Henry Moseley showed that atomic number, not atomic weight, better accounts for periodicity, leading to the current arrangement.

In the standard layout, rows are periods and columns are groups or families. There are 7 periods and 18 groups. The table is divided into s-, p-, d-, and f-blocks, reflecting electron configurations. Periodic trends include ionization energy, electronegativity, atomic radius, and electron affinity, which vary predictably across periods and groups.

Variants include the long-form and short-form representations, as well as extended tables that include synthetic elements up to oganesson (element 118). The lanthanide and actinide series appear often as separate rows. The Periodentafel supports chemistry, physics, materials science, and education by organizing properties and predicting reactivity.

Today, the periodic table remains a central organizing principle of chemistry, used to infer element properties, guide research, and communicate information about elements and compounds.