The periodic table of elements is an extremely important and useful scientific tool, especially in the field of chemistry, but also in many other scientific areas. It has been around for hundreds of years and has been continually added to and developed by many different scientists over time. The periodic table contains over 100 elements, each with different physical and chemical properties. The periodic table was not simply the work of one person who created and discovered all the elements, it was the combined work of many different scientists. However, Dimitri Mendeleev is often considered the creator or even the father of the periodic system. The first theory dealing with the atom was by Democritus and Leucippus who first proposed the idea of ​​the atom as an invisible particle of which all matter is made. However, the first real discovery of an element, other than those like gold and silver etc. (which people knew about before written history) was phosphorus, which was discovered by Henning Brand in 1649. In 1787, a French chemist called Antoine Lavoisier, made a list of all 33 known elements of the time. Between 1649 and 1869 the periodic table was added, and in 1869 a total of 63 elements were discovered. In 1864, John Newlands made a huge advance in the arrangement of these elements, as he was able to sort them by atomic weight and was also able to observe similar properties between the elements. The creation of the periodic table, however, is believed to be the work of the Russian scientist Dimitri Mendeleev who proposed a table as a classification system for all the elements that had been discovered and also left spaces for the elements that had not yet been discovered, but had predicted that they would have done it. The periodic table continues......center of paper......and looking back today it may not seem like he achieved much in terms of publishing a list of just five elements (1803) compared to the one hundred and twelve elements that we know today. But at the time it would have been huge, because at that time people knew very little about these elements, even because they were able to include their atomic numbers as well. Dalton also published a second list of elements in 1808, this time including 20 elements, along with their atomic masses and some combinations of elements. This was an improvement over his first list, but it still had rather imprecise atomic masses and was still quite far from the 112 elements we know today. However, this list was improved once again in its second volume, published in 1827, which again included 36 elements along with symbols and atomic masses..