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Lavoisier
Antoine-Laurent de Lavoisier was a French nobleman and chemist central to the 18th-century chemical revolution and had a large influence on both the history of chemistry and the history of biology. Because of his scientific work, mostly in geology, he was elected in 1768 at the age of 25 to the Academy of Sciences, France’s most elite scientific society. Lavoisier contributed to the periodic in many ways.He discovered and wrote the first extensive list of elements containing 33 elements as well -
Dobereiner
Between 1817-1829 Johann Dobereiner developed the triads which were groups of 3 elements with similar properties. For example: sodium, lithium and potassium formed a triad. Calcium, strontium and barium formed a triad, chlorine, bromine and iodine also formed a triad. -
Newlands
In 1863, John Newlands, an English chemist, proposed the Law of Octaves which stated that elements repeated their chemical properties every eighth element.The musical analogy was ridiculed at the time, but was found to be insightful after the work of Mendeleev and Meyer were published. -
Newlands
In 1864, he noticed that, if the elements were arranged in order of atomic weight, there was a periodic similarity every 8 elements. He proposed his ‘law of octaves’ on this. He arranged all the elements known at the time into a table in order of relative atomic mass. When he did this, he found that each element was similar to the element eight places further on. For example, starting at Li, Be is the second element, B is the third and Na is the eighth element. -
Meyer
He produced his own periodic table around the same time that Mendeleev did, and they were very similar
In 1864, Meyer formed a shortened version of the periodic table and included half of the known elements that we know of today
In 1868, Meyer made an extended version of the periodic table which he gave to a colleague to evaluate
The extended version was not published until 1870, which was a year after Mendeleev's table was published -
Mendeleev
Dmitri Mendeleev a Russian chemist and teacher published the first periodic table of elements in 1869. With the help of a set of cards Mendeleev organised and rearranged materials until patterns became evident. After rearranging the cards several times, he discovered that similarities and chemical behaviour occurred regularly when he placed them in order of increasing atomic mass. -
Seaborg
Glen Seaborg artificially produced heavy mass elements in 1940. These new elements were called actinides. The actinides are atomic numbers 94 to 102. After he discovered these elements he redesigned the periodic table and made how it is today