Development Of The Modern Periodic Table

Development of the Modern Periodic Table The Periodic Table of the Elements was developed out of a need for a database where information about the elements could be stored and accessed. People had known about some elements, such as copper, silver, and gold, since ancient times, since these elements are readily available in nature. The Greek Philosopher Aristotle thought that there were four elements: air, fire, water, and earth. This theory was proved false when individual elements began to be discovered. The first new element to be discovered was Phosphorus, which was discovered in 1649 by Henning Brand, a German merchant, who was distilling human urine in an effort to create the “Philosophers Stone”, a mythical stone that was said to turn metals into gold. In 1661, Robert Boyle defined an element as “a substance that cannot be broken down into a simpler substance by a chemical reaction.” (Wikipedia, History of the Periodic Table). Antoine-Laurent de Lavoisier was a French chemist and biologist in the 18th Century. He wrote Traité Elémentaire de Chimie, one of the first chemistry textbooks. In it, Lavoisier lists 33 elements grouped into four categories: gases, nonmetals, metals, and earths. (Dr. John Emsley, the Development of the Periodic Table). This was the foundation of the modern list of elements. He also lists light and caloric (believed to be a liquid part of heat, doesn’t exist) because he thought that these were items made of matter. In 1829, Johann Wolfgang Döbereiner was the first person to recognize periodicity or the undulations of properties of elements based on their atomic mass and other of its properties. (Wikipedia, The Periodic Table). Döbereiner’s Law of Triads, which stated that the atomic mass of the middle element of the triad was the average of the other two elements. By the year 1869, 63 elements had been discovered. Also in this