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The role of chemists

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Introduction

Open-Book Paper It was Lavoisier who divided the few elements known in the 1700's into four classes, and then John Dalton made atoms even more convincing, suggesting that the mass of an atom was it's most important property. In the nineteenth century Johann D�bereiner was the first to attempt to classify elements using their relative atomic mass. He also identified a number of 'triads' in the list of elements then known. Each triad was a set of 3 elements that have similar properties (e.g. Cl, Br and I; Ca Sr and Ba). In 1863, John Newlands noted that when the known elements were written in order of increasing relative atomic mass, every eighth element has similar properties. He called this the Law of Octaves. (There were only seven elements in each period at this time because the noble gases had not been discovered yet). ...read more.

Middle

In hot countries it becomes a liquid metal like mercury. It is also unusual because of its high boiling point (2403�C). It has the widest liquid range of any element. It shares the same property as water for being denser as a liquid than as a solid at its freezing point. Hence it will solidify from the top down. However it closely resembles a similar metal in its appearance (aluminium). Like aluminium, it dissolves in both acids and alkalis. Evolving hydrogen. Only a few metals behave in this way. These metals all have amphoteric hydroxides. The UNILAC accelerator involves firing a beam of relatively heavy ions from an accelerator towards a target of a heavy, stable element such as lead. If this is done with sufficient violence, the ions overcome the natural repulsion of the nuclei and fuse together, creating a new element. ...read more.

Conclusion

The role of chemists has dramatically changed over the past 200 years. Medieval chemists (alchemists) goal was to turn base metals into gold. As the years went by their role changed, in the 1700's they were now looking to discover and find new elements. Today they are creating the elements them self (synthesising new elements). Once the scientist had stopped discovering elements, they went about making their own this has only been possible due to our technology. The UNILAC accelerator has only just been invented in the past 20 years and so when it was invented it still took some years to synthesize the new elements and even then they don't last long because they have very short half lives. The advance of chemistry has mainly been down to the advances in technology. You could say that with out the advances in technology most of the discoveries man has made would not exist. In the future we are probably likely to find more elements and have a better understanding of the elements themselves. ...read more.

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