The History of the Periodic Table
The History of the Periodic Table
Since the ancient times, people like the Greeks were acknowledged of the existence of elements, but only knew of common ones like gold, tin, and copper. It wasn’t until the middle of the nineteenth century when about 50 elements were discovered and scientists began to wonder if the elements vary from each other or if a pattern is represented in the arrangement of the elements. A number of scientists tried different kinds of patterns. For example, the German scientist Johann Wolfgang Dцbereiner tried grouping the three halogens elements (chlorine, bromine, and iodine) in a consecutive order of atomic weights. The idea of putting the elements together finally took shape when the two scientists, Dmitry Mendeleev and Julius Lothar Meyer successfully arranged the order of the elements by their atomic weight and discovered that the properties of the elements recur in the same pattern. With the works of these scientists, the periodic table was created as well as the periodic law. With this set, scientists as of today had been able to organize the elements without much trouble and were able to discover unknown elements. Although there are many elements in the world and many of them have not always been known of, the periodic table had been created to classify these elements as well as the table’s corresponding patterns and trends.
During the ancient times, the philosopher, Aristotle made a proposal saying that there are four elements which are fire, water, earth, and wind. All of these elements can be combined in any ways to form other elements. Unfortunately, his theory was later disregarded after the identity of chemical elements began to be discovered. For centuries, the chemical elements had been cumulating since the discovery of the first element. Finally, there had been a point of time where scientists began to wonder if there is a pattern that can organize all the elements together. And also, scientists began wonder if any sort of relationship is present among the elements. It was during the 19th century when a number of scientists attempted to organize the elements together.
The earliest attempt in assembling the elements started with Johann Dцbereiner. Through his works, he discovered that certain elements can be grouped in threes. The pattern he found in this concept was that the atomic weight of one element of a group is midway between the atomic weights of the other two elements. Based on this concept, the law he found was the law of triad in 1829. The scientist, Alexandre-Йmile Beguyer de Chancourtois, was another scientist that made an attempt to group all the elements together in an order. He made a spiral graph that is plotted on a cylinder and put the elements in an order of increasing atomic weight in 1862. Unfortunately, his ideas were ignored by chemists because they were written in geologic terms. Lastly, the scientist, John Newlands proposed his ideas of arranging the elements together based on the atomic weight. Through his works, he discovered that every eighth element has similar properties and created the Law of Octaves.
The periodic table was finally created by Mendeleev and Meyer and was revised later by other scientists. Meyer first introduced the idea of the periodicity of atomic volume against the atomic weight. Using this idea, he created a graph showing a series of sharp peaks. He found that elements with similar chemical properties take place at comparable points on the various peaks. The periodic table that Mendeleev created allowed him to predict new elements because after all the elements were assembled, gaps were leftover giving him hints as to find out what kind of properties the unknown elements have. According to the periodic table Mendeleev created, he organized the elements in rows and groups based on the atomic number. In addition to this table, the periodic law was created by the scientist, Henry Moseley. This law stated that an element’s properties are the mechanisms of its atomic number. The periodic table is structured in certain ways. In a period, the atomic radius decreases as the atomic number increases from left to right. Also, from moving from left to right, the number of protons increases as well as the electrons because the positive charge increases in the nucleus causing the strengthening of its attraction toward electrons.