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Attempts to classify the elements began in early 19th century, by the grouping of elements which sha

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Attempts to classify the elements began in early 19th century, by the grouping of elements which shared similar chemical characteristics. The German chemist Johann Dobereiner succeeded in formulating a mathematical relationship between the relative atomic masses of sets of three elements, which he called 'triads', however scientists later found that the atomic weight relationship of elements extended beyond this. The first to arrange the elements into a table was the English scientist John Newlands. According to his 'Law of Octaves', he noticed that if the 62 known elements of the time were put in order of increasing relative atomic mass, then after intervals of eight similar properties could be observed. However, due to inaccuracies within his measurements, there were errors within his table and therefore his table was not accepted. Newlands table of elements - original version at http://web.fccj.org/~ethall/period/period.htm It was the Russian chemistry professor, Dimitri Mendeleev who achieved a periodic table of elements on which the modern version is based today, positioning the elements in regular intervals by atomic mass and similarities in their chemical properties. Within it, he not only acknowledged that there were elements left to be discovered by leaving spaces for them, but also made detailed predictions about their chemical properties. ...read more.


It possesses the property of having the largest liquid range, with a boiling point of 2403�, which is very strange for a metal, as metals are considered to be solids rather than liquid in the first place. It is probably the fact that solid metal is less dense than liquid form, which is the most bizarre property of gallium. This unique property, which gallium shares with water, suggests that gallium is a non metal rather than a metal, which all are denser as a solid than a liquid. Image from www.vanderkrogt.net/elements/ elem/ga.html Gallium's chemical properties are closely similar to those of aluminium. Like aluminium, it reacts with both acids and alkalis to give hydrogen. The reaction shows that gallium produces amphoteric hydroxides, which is something very few metals do. Another chemical property of gallium which is rare amongst metals, is the formation of anhydrous trichloride, (Ga2Cl6), one that is also shared with aluminium. Both these properties suggest that gallium is not a metal. Another strange property which also shows this, is the strange structure of gallium chloride (empirical formulae GaCl2), which can be written as GaCl.GaCl3. ...read more.


It is evident that the understanding of atomic structure was used by the inventors, as the apparatus relies entirely on the theory that overcoming the natural repulsion between two nuclei will allow them to fuse together as one. This is done by firing a heavy ion beam at another heavy element such as lead. If the beam bombards the heavy element at a high enough force, the nuclei will fuse together, to produce a new element. The UNILAC accelerator and the method of fusing atomic nuclei have been used to synthesise elements 92 to 114 of the periodic table over the last 25 years. This has not only broadened our understanding of chemical elements, but also allowed us to view atomic structure from a different perspective. After the discovery of gallium in 1875, atomic spectroscopy enabled the discovery of the remaining naturally occurring elements and was used until the early 20th centuries by scientists as the primary method of finding new elements. However, after this no more additions could be made to the periodic table using atomic emission spectrometry, and thus scientists changed their concept of discovering elements to synthesising new elements. This brought about the invention of the UNILAC accelerator, which allowed them to fuse two existing atomic nuclei into a synthesised nucleus of a new element. ...read more.

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