The+Periodic+Table

====---The periodic table of elements shown above is a tabular expression of the trends and characteristics of the earth's elements. ==== ====This table, to the naked eye, shows only the atomic number and atomic mass along with each elements chemical symbol, however, it shows much much more. ====

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- Second, each element is categorized into one of four blocks.

These block are referred as the s, p, d, and f blocks of the periodic table.
====The placement of the elements in these blocks is determined by the number of electron they have in their outermost energy levels. ==== ====The s-block contains groups 1A and 2A of the table, the d-block contains groups 3B - 12B, the p-block contains groups 13A - 18A, and the f-block contains the elements 57 - 70 and 89 - 102. ==== ====The similarity of their valence electron configuration will then determine which elements are to be placed in which part of the table, this begins a pattern. ====

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- As one can see the properties above also tie into the characteristics already listed and narrow the placement of each element down even further. - In the day of Dmitri Mendeleev and several other scientist they were simply given the huge list of elements and told to place them in a logical table or chart in which made sense. In doing so, Mendeleev created the first periodic table of elements. <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">He ,of course, looked at multiple similarities and differences like the ones listed above but he also took into account many other traits of each element. <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">The most prominent being each elements atom mass, ionization energy, and electronegativity. <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">These, however, were not the only characteristics Mendeleev looked at but he found the most comparison between those three. <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">This was only the beginning for Mendeleev and many others in the discovery and formation of the periodic table of elements. <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">-"Curran, Lesson 3-4" <span style="color: #808080; font-family: Georgia,serif; font-size: 150%;">"Google"