From the earliest history of man, Empedocles, the Greek philosopher, was the first to theorize that everything in the cosmos consisted of four components, earth, air, fire and water. Approximately 700 years later, Aristotle espoused that there was indeed four “roots,” as he called them, that make up all matter and he championed the theory put forth by Empedocles. Later Plato changed the name of these conceptual components to “elements,” however the exact nature of these four elements, earth, air, fire and water, were unknown.
In 1649, a bankrupt German merchant, Hennig Brand, while attempting to find a way to turn cheap metals into gold, discovered phosphorus, but it wasn’t until nearly forty years later, in 1689, that Robert Boyle defined it as an element of matter. Boyle put forth the hypothesis that a substance that cannot be broken down into a simpler substance, by means of chemical reaction, is a component or an element of matter. In 1789, Antoine Laurent de Lavoisier, published a list of elements, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulfur, in his book, Elementary Treatise of Chemistry. In his book he divided base elements into metal and non-metal categories, but it was not a comprehensive analysis of the elements. In 1817, Johann Wolfgang Dobereinerbegan to classify elements in “triad” groups which meant that the atomic weight of the second element was almost the exact average of the atomic weights of the first and third element. Ninety years later, there were a total of 63 known elements and scientists had discovered patterns in the atomic weights of these elements and but were searching for a way to classify them in an understandable way.
In 1862, Alexandre-Emile Beguyer de Chancourtois, a French geologist, published his paper in which he theorized that like elements occur at regular intervals when listed by their atomic weights, however, he didn’t put them in a diagram that illustrated the vertical alignment of the elements. It wasn’t until Dimtri Mendeleev, a Siberian-born Russian chemist, devised the periodic table, similar to the one we are familiar with, that this alignment could be seen. Although Mendeleev had made the relationship of the similar elements clear, he did not include the noble gases or isotopes since they had not been discovered as yet. In 1914, Henry Moseley revised Mendeleev’s periodic table and put the then known elements in a sequential order based on their nuclear charge rather than their atomic weight.
Although the periodic table is standard in chemistry class today, there are new theories that are constantly being proposed by scientists to further explain the properties of elements on the periodic table. In 2007, Jozef Garai, from Florida International University, proposed a mathematical formula to describe the sequences of integers of the elements in the periodic table.
It remains to be seen what changes will be made to the periodic table we know today, or what new elements will be discovered and theories will be proposed due of the burgeoning exploration of not only our planet, but of the planets in our solar system and beyond.