The periodic table turns 150 next year. Given that all scientific concepts are eventually refuted, the durability of the periodic table would suggest an almost transcendent quality that deserves greater scrutiny, especially as the United Nations has nominated 2019 as the year of the Periodic Table. These days it seems that physics gives a fundamental explanation of the periodic table, although historically speaking it was the periodic table that gave rise to parts of atomic physics and quantum theory. I am thinking of Bohr’s 1913 model of the hydrogen atom and his extension of these ideas to the entire periodic table.
The main thing that drew me to the history and philosophy of science was the simple desire to understand the nature of science. I was introduced to the exciting ideas of Popper, Kuhn, Lakatos and Feyerabend, but it soon became clear that there were serious problems with each of these views and that those heydays were long gone. Professionals in the field would no longer presume to generalize as boldly as the famous quartet had done.
Our story has to begin somewhere and why not with the Manchester schoolteacher John Dalton who revived the atomic theory of the ancient Greek philosophers? In addition to supposing that the ultimate components of all matter were atoms, Dalton set about putting this idea on a quantitative foundation. He published the first list in which he compared the weights of the atoms of all the elements that were known at the time.
This blog post concerns a virtually unknown chemist, John David Main Smith, who contributed a significant piece of research in atomic physics in the early 1920s at the time when knowledge of the field was undergoing very rapid changes. Main Smith is so little known that I had to search far and wide for a photograph of him before finally obtaining one from his son who is still living in the south of England.
The recent announcement of the official ratification of four super-heavy elements, with atomic numbers 113, 115, 117 and 118, has taken the world of science news by storm. It seems like there is an insatiable appetite for new information about the elements and the periodic table within the scientific world and among the general public.
One of the most interesting developments in the history of chemistry has been the way in which theories of valency have evolved over the years. We are rapidly approaching the centenary of G.N. Lewis’ 1916 article in which he proposed the simple idea that a covalent bond consists of a shared pair of electrons.
One of the central concepts in chemistry consists in the electronic configuration of atoms. This is equally true of chemical education as it is in professional chemistry and research. If one knows how the electrons in an atom are arranged, especially in the outermost shells, one immediately understands many properties of an atom…
The discovery of the periodic system of the elements and the associated periodic table is generally attributed to the great Russian chemist Dmitri Mendeleev. Many authors have indulged in the game of debating just how much credit should be attributed to Mendeleev and how much to the other discoverers of this unifying theme of modern chemistry.
The past couple of years have seen the celebration of a number of key developments in the history of physics. In 1913 Niels Bohr, perhaps the second most famous physicist of the 20th century after Einstein, published is iconic theory of the atom.
The usual version of how Mendeleev arrived at his discovery goes something like this. While in the process of writing his textbook, ‘The Principles of Chemistry’, Mendeleev completed the book by dealing with only eight of the then known sixty-three elements. He ended the book with the halogens.