Essay Example on There are many scientists and inspirational People

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There are many scientists and inspirational people whose actions and discoveries all contributed to the build up of today s periodic table Today s table is broken down into element s atomic number periodic trends electron configurations and recurring chemical properties The main periodic trends in the table are the atomic radius ionization energy electronegativity and electron affinity Atomic radius patterns are observed throughout the periodic table and atomic size gradually decreases from left to right across a period of elements This is because within a period or family of elements all electrons are added to the same shell Why is the periodic table so important Well the table is very useful for today's scientists and students as it helps to predict the types of chemical reactions that are likely for any element that has been found There are many patrons that supported the creation of today s periodic table but the four scientists that have been very crucial it is Dmitri Mendeleev Henry Moseley William Ramsay and Lothar Meyer Lothar Meyer In 1864 five years before the first announcement of a Periodic System by Mendeleev Lothar Meyer had produced a table of just 28 elements 



He listed the elements by their valence and were almost entirely main group elements Meyer incorporated transition metals in another table in 1868 which listed the elements in increasing weight order with elements with the same valence in a given column This was ahead of Mendeleev's table 1869 however sadly Meyer s wasn t printed till 1870 Dmitri Ivanovich Mendeleev and Lothar Meyer were both unaware of each other s work until after this Later Meyer admitted that the Russian had first published about the Periodic System by saying that his ideas matched those of Mendeleev However Meyer s main contribution was his recognition of periodic behavior Periodic behavior is simply a repeating pattern of a property shown on a graph In the case of Meyer the property he chose was the atomic volume of an element and he plotted it against its atomic weight Dmitri Mendeleev was a Russian chemist who developed the periodic classification of the elements

Mendeleev found that when all the known chemical elements were arranged in order of increasing atomic weight the resulting table displayed a recurring pattern or periodicity of properties within groups of elements In his version of the periodic table in 1871 he left gaps and spaces in places where he believed elements not founded would eventually find their place Dmitri even predicted the likely properties of three of the potential elements The proof of many of his predictions within his lifetime brought fame to Mendeleev as the founder of the Periodic Law The Periodic Law also known as Mendeleev's Law states that the physical and chemical properties of the elements repeat in a systematic and predictable way when the elements are arranged in order of increasing atomic number While Mendeleev is perhaps the most important contributor to the development of the periodic table he did not create it from scratch His work inspired many other scientists to dive deeper into finding new elements and determining new properties that have not yet been discovered Mendeleev s actions were so important for the future of science and the world 



His work of arranging elements according to their similar properties allow scientists to easily tell the characteristics of an element by just looking at its positioning on the table In 1892 William Ramsay found what Dmitri Ivanovich Mendeleev couldn t noble gases Ramsay s curiosity was piqued by Lord Rayleigh s observation that the density of Nitrogen atomic number seven extracted from the air was forever bigger than Nitrogen released from numerous chemical compounds Ramsay then set searching for an unknown gas in the air of bigger density which he named Argon During his investigation for the presence of Argon in a very uranium bearing mineral he instead discovered Helium Helium had been known since 1868 however solely within the sun This second discovery led him to suggest the existence of a brand new cluster of components within the table Ramsay and his coworkers quickly isolated the elements Neon Krypton and Xenon from the Earth's atmosphere Lastly Henry Moseley is a very important contributor to the gradual creation of today s periodic table because he explored the atomic number which is what the modern table is chronologically ordered in and further increased knowledge on the atom

Henry Moseley was an English scientist who through an experiment demonstrated that the foremost properties of an element are determined by the atomic number not by the mass and firmly established the link between number and therefore the charge of the atomic nucleus His initial research was involved with radioactivity and beta radiation in radium Moseley measured the frequency of the X rays given off by different elements Each element gave off a different frequency that was related to the position of the element in the Periodic Table which measuring the element s atomic number Henry Moseley said that the atomic number must be the number of positive charges on the nucleus His thoughts were later confirmed by others and proved that there are just 92 elements up to uranium In a paper printed in 1913 he announced atomic numbers not masses determine the characteristics of chemical properties later called Moseley's law This discovery was a milestone in advancing the knowledge of the atom In 1914 Moseley printed a paper during which he concluded that there have been 3 unknown elements between aluminum and gold He also properly pointed out that there have been ninety two parts up to uranium and fourteen rare earth elements This information was a huge asset to organizing elements on a periodic table


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