Chemistry, asked by cutefam1235, 11 months ago

Essay on the greatness of Mendeleev and his periodic table

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Answered by anushkapchaudhari9
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Answer:

Explanation:

Development of the Periodic Table

Introduction:

The Periodic Table of Elements is a table that arranges all known chemical elements by order of their atomic numbers. During the 1600s, vast amounts of knowledge about the properties of elements and their compounds were discovered and by 1869 63 elements had been discovered. As more and more elements were discovered, scientists began to recognise similarities between their properties and began to devise means of classification. Thus the periodic table of elements was created. The current periodic table contains 117 elements, however more may yet be discovered. The elements in the periodic table are classified in groups, periods and blocks. Groups refer to elements with similar properties and…show more content…

While constructing the table, Mendeleev realised that some elements did not fit if he ordered them using their accepted masses. Thus he reordered elements; for example he changed the atomic weight of beryllium from 14 to 9 so that it was located with elements that its properties better matched. Mendeleev changed the weights of 17 elements, yet realised that his table was still incomplete. By looking at the gaps in his table, Mendeleev predicted the existence and properties of elements that were yet to be discovered. By finding a gap between the elements silicon and tin, Mendeleev predicted the element eka-silicon, and then similarly the elements eka-aluminium and eka-boron. His predictions of these unknown elements are what provided the most evidence for the validity of his table as his predicted elements were later discovered as gallium, germanium and scandium and their properties closely resembled those that Mendeleev had predicted. However, Mendeleev’s table was flawed in one aspect. He had built it based on the belief that the chemical properties of elements were based on their atomic weights and thus he made little other progress.  

Discoveries that led to the creation of Mendeleev’s table of elements:

It was only possible, however, for Mendeleev’s table to be created and thus progress to the form in which we know it now due to the efforts of various other scientists in discovering information that changed the theory around the

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