Periodic table

The semiweekly table was number one discovered almost cc or more years ago. In 1869, the German chemist, Julius Lothar Meyer and the Russian chemist, Dmitri Mendeleev, one by one published results which support the ideas of periodicity suggested a few years earlier by John Newlands. Meyer plotted various sensual properties (melting points, boiling points, density) of the know elements against their relative atomic pluralityes. The first graphical record was obtained by plotting molar volume against the relative atomic mass; he noticed that elements in the same chemical family occurred at mistakable points on the curve. E.g. lithium, sodium and potassium appe atomic number 18d on the peaks whilst fluorine, centiliter and bromine appeared honest before the peaks. Although Meyers curves showed a periodic repetition of properties with relative atomic mass, most of the credit for arranging the elements in a periodic table is given to Mendeleev. Mendeleev arranged the 60 or so elements known to him in stage of increase relative atomic mass, and showed that elements with connatural properties recurred at regular intervals. His first table showed that elements with similar properties fall in the same upright column. These columns of similar elements are called groups and the horizontal rows of elements are called periods. Mendeleevs table had gaps; he left gaps in his table in send that similar elements would fall in the same vertical column. What is more, he suggested that, in due course, elements would be discovered to fill these gaps and he as well as predicted properties for whatsoever of the missing elements. Within Mendeleevs own lifetime some(a) of these missing elements were discovered and their properties coincided very closely with his predictions. Mendeleev also proposed that periods 4, 5, 6 and 7 should contain more than seven elements. In order to fit these longer periods into his pattern, he divided them into... If you want to hit the books! on a full essay, order it on our website: OrderEssay.net

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