Early Scientists
One of the earliest scientists to organize the known elements of man in one table was German chemist Johann Dobereiner. In 1817, Dobereiner noticed that groups that contained three specific elements had certain patterns, such as the atomic weight of one element would be halfway between the other two atomic weights. He kept on researching, and in 1829, he proposed the Law of Triads. His pioneering work gave way to other scientists who also attempted to produce a periodic table. About 40 years later, in 1862, French geologist Alexandre-Émile Beguyer de Chancourtois formed a graph that spiraled around a cylinder. In this graph, the elements were ordered by expanding atomic weight, and alike elements lined up vertically. He was the first to notice that when elements were organized by atomic weight, then like elements appeared regularly. This was the periodicity of the elements.The following year, in 1863, English scientist John Newlands observed that every eighth element had like characteristics. He called his observations the Law of Octaves. |
Dmitri Mendeleev
Dmitri Mendeleev was a Russian chemist and inventor born on February 8, 1834 in Tobolsk, Russia. Although there were others that thought of the periodic table before him, Mendeleev is the scientist credited with the creation of the periodic table. He is also known as the father of the periodic table. In 1865, when Mendeleev was 31, he began working at the Saint Petersburg University. While he was teaching, he published his two-volume book, Principles of Chemistry, in 1868. The research he conducted while writing his book led to the formulation of his own periodic table. The next year, on March 6, 1869, Mendeleev presented his new discovery about the elements and how they are related to the Russian Chemical Society. That same year, Mendeleev published the periodic table in his new book, "On the Relationship of the Properties of the Elements to their Atomic Weights." Mendeleev's periodic table contained the most accurate values of an element's atomic mass, and left blank spaces for unknown elements. |
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Julius Lothar Meyer
Another man, although less known, credited for partly discovering the periodic table is Julius Lothar Meyer. Meyer was born on August 19, 1830, in modern-day Germany. In 1862, Meyer published his book called, Die modernen Theorien der Chemie. In this book, there was an early version of the periodic table. On this periodic table, there were 28 elements, and they were organized according to their valence. This was the first time that elements were grouped according to the number of their valence electrons. Technically, Meyer was the first to build the periodic table in 1864, although it was very primitive. However, while Mendeleev published his much more complex periodic table in 1869, Meyer published his newly revised periodic table a few months later. These two periodic tables were nearly identical. The difference between Meyer and Mendeleev's periodic table was, while Mendeleev's periodic law was formed on atomic mass, Meyer's periodic law was based on atomic volume. |
By: Catherine Tang