Guest author, Thomas Kennedy, features a twice-monthly series, Quantum Leap, wherein he guides readers through the fascinating world of quantum mechanics. This is issue 009.
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So the question is, “what is Elemental?” In 1661, Robert Boyle determined that something that can’t be broken-down by a chemical reaction is an element, a notion, according to Wiki, that held for almost 300 years and a definition I still recall from high school chemistry class. This was a major moment in the process of understanding what the underlying building blocks of life are. Now, for the first time, man had a tool and a way to codify his approach to answering the questions of what is fundamental.
By 1869, a total of 63 elements had been discovered. As the number of known elements grew, scientists began to recognize patterns in properties and began to develop classification schemes. Attempting to understand this pattern and how to best organize it led to the development of the Periodic Table of Elements.
There has been some disagreement about who deserves credit for being the “father” of the periodic table – the German, Lothar Meyer, or the Russian, Dmitri Mendeleev. Both chemists produced remarkably similar results at the same time, working independently of one another. Meyer’s 1864 textbook included a rather abbreviated version of a periodic table used to classify the elements. This consisted of about half of the known elements listed in order of their atomic weight and demonstrated periodic valence charges as a function of atomic weight. In 1868, Meyer constructed an extended table which he gave to a colleague for evaluation. Unfortunately for Meyer, Mendeleev’s table became available to the scientific community via publication (1869) before Meyer’s appeared (1870).*
Mendeleev created a card for each of the 63 known elements. Each card contained the element’s symbol, atomic weight, and its characteristic chemical and physical properties. When Mendeleev arranged the cards on a table, in order of ascending atomic weight grouping elements of similar properties together, (in a manner not unlike the card arrangement in his favorite solitaire card game, patience,) the periodic table was formed. From this table, Mendeleev developed his statement of the periodic law and published his work On the Relationship of the Properties of the Elements to their Atomic Weights, in 1869. The advantage of Mendeleev’s table, over previous attempts, was that it exhibited similarities not only in small units such as the triads, but showed similarities in an entire network of vertical, horizontal, and diagonal relationships. In 1906, Mendeleev came within one vote of being awarded the Nobel Prize for his work.*
For the next installment, “Charge!”
Watch for Issue #10 of Thomas’ “Quantum Leap”, here on A Sky Full of Stars, on March 19, 2010.
*Western Oregon University citation
