Perioodilisustabelit

Perioodilisustabelit is the Estonian term for the periodic table of elements. It is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties. This arrangement displays periodic trends, such as elements with similar behavior placed in the same columns.

The table is organized into periods, which are the horizontal rows, and groups, which are the vertical columns. Elements within the same group share similar valence electron configurations, leading to similar chemical properties. The periods correspond to the principal energy level of the outermost electrons. The periodic table is a fundamental tool in chemistry, providing a systematic way to understand and predict the properties of elements and their interactions.

Dmitri Mendeleev is credited with developing the first widely recognized periodic table in 1869. He arranged the elements based on their atomic weight and observed recurring properties. His table was remarkably accurate and even predicted the existence and properties of undiscovered elements. Modern periodic tables are based on atomic number, a concept developed later, which provides a more precise ordering of elements. The table has evolved over time with the discovery of new elements and a deeper understanding of atomic structure.