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Antoine Lavoisier makes the first list of elements
Antoine published the first book of chemesty including a list of 33 substances he belived to be elements. He included things such as oxegenn nitrogen and meruary. He also incliuded light and caloric because he believed they were material substances. -
Johann Wolfgang groups elements
Johann Wolfgang groups elements into groups of three with similar chemicals. He then discovered that the middle element had atomic mass close to the other two elements atomic mass. -
Valency
August Kekule discovered that some elements tend to bond to other elements. This became hnown as valency. -
John Newland groups elements
John Newland groupes elements in order of increacing atom mass and discoveres that the element 8 places behide it has simlar chariteristics. -
Dmitri Mendeleev creates the first periodic table
In 1896 Dmitri Mendeleev created the periodic table by placing the then known 65 elements and placing them in a table so that each element had a higher atomic mass than the one left of it and putting elements with similar chemical properties in the same column. When Dmitri finished the table he found that there were blank spaces where undiscovered elements should be. Dmitri was able to guess the atomic height and chemical properties of elements before they were discovered. -
Gallium is found
Gallium was found and it has the same chemical properties as Dmitri estimated. -
Scandium is found
Scandium is found and it like Gallium had the same chemical properties as Dmitri predicted. These two elements added proved that Dmitri's table is realiable. -
Period: to
Noble gasses are dicovered
During this timespand the nobel gases where discovered. When the noble gasses were discovered this put a whole in Dmitri's periodic table because there where no noble gasses discovered when Dmitri made his table and he didn't expect a whole coloum to be missing. -
Henry Moseley develops on the current periodic table
Henry shot electrons at atoms and caused x-ray to be emitted and found that the frequency of x-rays realised increased in an interesting pattern and concluded that the positive charge increased by one as the atomic number goes up. This meant that an elements location on the periodic table is better estimated by its atomic number rather than its atomic mass as Dmitri thought. He then re-wrote the periodic table using its atomic number rather than on atomic mass. -
Mendelevium is found
Mendelevium is found and is named in honour of Dmitri Mendeleev. -
Higgs Boson Discovered
Higgs Boson, the last undiscovered element, was proved to exist in 2012 by Peter Higgs. The exact properties of the partical still hasnt been discovered. The Higgs Boson has been doubed by some as the "god partical' because it is belived to to have be existant seconds after the big bang and then it decayed into other paricals to form all elements. Some scienties also belive there could be more than one type of Higgs Boson.
