Who Invented the Periodic Table?
The periodic table is central to the study of chemistry, and it's used to organize chemical elements in a coherent way. The development of the periodic table has a long history that involves many scientists over hundreds of years. But who actually invented it? How did the periodic table evolve over the years? Why did the inventor of the table organize it in the way that we use it today?
There were many people who contributed to the ideas behind the periodic table, but some figures are credited more for its development than others.
Developments in Ancient Times
Going back to ancient times, we can see the roots of our understanding of the elements that make up the periodic table. In ancient Greece, Aristotle and Plato thought that everything on the planet came from four root sources. They were fire, water, air and earth. Therefore, we can say that the ancient Greeks did understand the nature of elements and what they were in a basic way. But they didn't do much to advance our understanding of matter; that is something that would come later.
17th and 18th Century Discoveries
It's in the 17th and 18th centuries that we can start to see the origins of the periodic table, which is tied to the discovery of the first chemical elements. Hennig Brand conducted experiments that led to his discovery of phosphorus in 1669. This was the first discovery of an element. Antoine-Laurent de Lavoisier wrote the first modern textbook on chemistry in 1789. This book listed the basic elements, which were defined to be the smallest particles of matter that couldn't be subdivided any further. It was the basis for our modern understanding of the elements.
The Input of John Newlands
John Newlands was a very important figure in 19th century chemistry. He was the first chemist to take the list of known elements at that time and separate them into different groups. This is something that would later be very important when the first proper periodic table was produced. He proposed a law of octaves to separate and divide up the elements. This was because he noticed a similarity in the atomic weight and physical properties of the chemicals in every 8 chemicals in his list. His discoveries were first published in Chemistry News in the mid-1860s.
The word ‘periodic' comes from his work and discoveries, so his impact on the modern periodic table is clearly very important. There are even some people who still credit him as the main driving force behind the development of the periodic table of elements. In recent years, the Royal Chemistry Society has formally acknowledged his impact and contribution. However, he is not considered the most important contributor to the invention of the periodic table.
Other 19th Century Contributions
In 1862, a french geologist named Alexandre-Emile Béguyer de Chancourtois was the first person to notice the periodicity of chemical elements. His findings predate those of John Newlands who did similar work in this area of chemistry. He wrote down a different early form of a periodic table which was organized by atomic weight, but it's not the same as the one that we know and recognize today.
Johann Wolfgang Döbereiner worked several years before Alexandre-Emile Béguyer de Chancourtois, and he also attempted to group together chemical elements. He was one of the first to do so. He used groups of three to organize the elements, and he called these groupings triads. For example, he would group together chlorine, bromine and iodine. They were grouped according to chemically analogous elements, and they increased in atomic weight. This work was done in the late 1820s, and had an impact on the chemists that followed him and did other work on the grouping of chemical elements.
Dmitri Mendeleev: The Man Credited as the Inventor of the Periodic Table
This is the name that is most commonly associated with the invention of the periodic table. Up to this point in time, there was a clear progression towards the concept of a periodic table in the early 19th century. Dmitri Ivanovich Mendeleev, however, was the first person that made a periodic table that was very close to the one we today. Mendeleev's table consisted of the 60 elements that were known at the time. He was a Russian chemist, and he was focused on arranging the elements according to their atomic mass. The formal presentation of his ideas from 1869 was called The Dependence Between the Properties of the Atomic Weights of the Elements. Later that year his periodic table was published in a Russian journal.
He found that when his periodic table was arranged in order of increasing atomic mass, patterns emerged in the elements in the table at regular intervals. This meant that predictions could be made regarding physical properties of elements that haven't even been discovered yet. Further, he also predicted that other elements of various atomic mass would be discovered in the future, and left spaces for those elements in his table.
Lothar Meyer: The Periodic Table's Co-Creator?
Although Mendeleev is seen as the main person behind the invention of the periodic table, this is not a settled issue. There were other people doing similar work at the same time. Many people consider Lothar Meyer as being the rightful co-creator of the modern periodic table alongside Mendeleev. His table ordered elements according to repeating patterns and physical properties, much like Mendeleev's. Meyer's work is still very impressive and important. However, the two tables were not the same, and Meyer's was lacking in some key ways.
For example, Meyer's table was not ordered by atomic weight. Instead, Meyer's table was organized by valence, which is a measure of how readily elements combine with other elements to form compounds. His work was published roughly 5 years before Mendeleev's and consisted of a table of 28 elements. In the end, Mendeleev is considered the inventor of the periodic table because his arrangement of the elements allowed for accurate prediction of properties of elements that weren't known at the time.
Additional 20th Century Contributions
The development of the periodic table did not come to a halt at the end of the 19th century. There were further developments and discoveries that took place as recently as the first half of the 20th century. Henry Moseley is the most prominent contributor to the periodic table in the 20th century. A year before he died in World War 1, Moseley found that the X-ray wavelength of an element has a relationship with its atomic number.
This led him to place cobalt and nickel in the correct order on the periodic table. His discovery also led him to find that there should be more gaps on the periodic table, and these have now been filled by other elements that have since been discovered. In the 1940s, Glenn T. Seaborg discovered while working on Manhattan Project the correct arrangement of the actinide and lanthanide series on the modern periodic table.
Why is the Periodic Table Organized the Way it Is?
A natural question is why is the periodic table organized the way it is? It all comes down the grouping of elements. When the table is arranged according to the elemental atomic mass, physical properties of the elements emerge in a periodic fashion. About two-thirds of the table is taken up by metals on the left. And then the right-hand side of the table is dedicated to the nonmetals. There is a small strip of elements separating these two sections that are known as the metalloids.
The periodic table is always under review, and properties of elements are continually being discovered. The periodic table changes as new elements are discovered, which happens as new elements are momentarily created in particle accelerators and other nuclear experiments. The periodic table is a tool that is used by all branches of science and engineering, and makes complex problems easier to solve.