TITLE : Periodic table
The periodic table, also known as Mendeleev's table, is a table of the chemical elements existing on Earth. The Russian chemist Dmitri Mendeleev is credited with its creation in 1869, although less extensive tables existed before this. He intended to display the patterns apparent in the chemical properties of each element. Since its original creation, new elements have been discovered and added to Mendeleev's initial table. STRUCTURE
The structure of the periodic table is very significant. The current table holds 117 elements in a very distinct order for the purpose of showing similarities and differences in chemical properties. Out of all of the elements, 94 are found in nature and the other 24 were synthetically produced with particle accelerators. As well, most copies of the periodic table separate the metal and non-metal elements with a dark stair-step line. The metals are on the left and the non-metals on the right. Additionally, elements are placed in order of increasing atomic number, which is the number of protons in the nucleus of the element's atom. The rows are also organized so that elements with similar properties are found in the same columns. Within each element square, information on the element's symbol, atomic number, atomic mass, electronegativity, electron configuration, and valence numbers can be found. At the bottom of the periodic table is a two row block of elements that contain the lanthanoids and actinides. These groups are classified as inner transitional metals.
The chemical elements classified into groups, periods, and blocks. Groups, also referred to as a families, are the vertical columns located on the periodic table. Groups are considered to be the most significant form of classification. Many groups contain elements with very similar properties and are referred to with special names such as the halogens and alkaline earth metals. Periods are made up of the...
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