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When people think of evolution, many reflect on the concept as an operation filled with endless random possibilities–a process that arrives at advantageous traits by chance. But is the course of evolution actually random? In A World from Dust: How the Periodic Table Shaped Life, Ben McFarland argues that an understanding of chemistry can both explain and predict the course of evolution.

The post How does chemistry shape evolution? appeared first on OUPblog.

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.

The post Those four new elements appeared first on OUPblog.

How can an element be lost? Scientists, and the general public, have always thought of them as being found, or discovered. However, more elements have been “undiscovered” than discovered, more “lost” than found.

The post The undiscovered elements appeared first on OUPblog.

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.

In fact the discovery of the periodic table represents one of a multitude of multiple discoveries which most accounts of science try to explain away. Multiple discovery is actually the rule rather than the exception and it is one of the many hints that point to the interconnected, almost organic nature of how science really develops. Many, including myself, have explored this theme by considering examples from the history of atomic physics and chemistry.

But today I am writing about a subaltern who discovered the periodic table well before Mendeleev and whose most significant contribution was published on 20 August 1864, or precisely 150 years ago. John Reina Newlands was an English chemist who never held a university position and yet went further than any of his contemporary professional chemists in discovering the all-important repeating pattern among the elements which he described in a number of articles.

Newlands came from Southwark, a suburb of London. After studying at the Royal College of chemistry he became the chief chemist at Royal Agricultural Society of Great Britain. In 1860 when the leading European chemists were attending the Karlsruhe conference to discuss such concepts as atoms, molecules and atomic weights, Newlands was busy volunteering to fight in the Italian revolutionary war under Garibaldi. This is explained by the fact that his mother was Italian descent, which also explains his having the middle name Reina. In any case he survived the fighting and set about thinking about the elements on his return to London to become a sugar chemist.

In 1863 Newlands published a list of elements which he arranged into 11 groups. The elements within each of his groups had analogous properties and displayed weights that differed by eight units or some factor of eight. But no table yet!

Nevertheless he even predicted the existence of a new element, which he believed should have an atomic weight of 163 and should fall between iridium and rhodium. Unfortunately for Newlands neither this element, or a few more he predicted, ever materialized but it does show that the prediction of elements from a system of elements is not something that only Mendeleev invented.

In the first of three articles of 1864 Newlands published his first periodic table, five years before Mendeleev incidentally. This arrangement benefited from the revised atomic weights that had been announced at the Karlsruhe conference he had missed and showed that many elements had weights differing by 16 units. But it only contained 12 elements ranging between lithium as the lightest and chlorine as the heaviest.

Then another article, on 20 August 1864, with a slightly expanded range of elements in which he dropped the use of atomic weights for the elements and replaced them with an ordinal number for each one. Historians and philosophers have amused themselves over the years by debating whether this represents an anticipation of the modern concept of atomic number, but that’s another story.

More importantly Newlands now suggested that he had a system, a repeating and periodic pattern of elements, or a periodic law. Another innovation was Newlands’ willingness to reverse pairs of elements if their atomic weights demanded this change as in the case of tellurium and iodine. Even though tellurium has a higher atomic weight than iodine it must be placed before iodine so that each element falls into the appropriate column according to chemical similarities.

The following year, Newlands had the opportunity to present his findings in a lecture to the London Chemical Society but the result was public ridicule. One member of the audience mockingly asked Newlands whether he had considered arranging the elements alphabetically since this might have produced an even better chemical grouping of the elements. The society declined to publish Newlands’ article although he was able to publish it in another journal.

In 1869 and 1870 two more prominent chemists who held university positions published more elaborate periodic systems. They were the German Julius Lothar Meyer and the Russian Dmitri Mendeleev. They essentially rediscovered what Newlands found and made some improvements. Mendeleev in particular made a point of denying Newlands’ priority claiming that Newlands had not regarded his discovery as representing a scientific law. These two chemists were awarded the lion’s share of the credit and Newlands was reduced to arguing for his priority for several years afterwards. In the end he did gain some recognition when the Davy award, or the equivalent of the Nobel Prize for chemistry at the time, and which had already been jointly awarded to Lothar Meyer and Mendeleev, was finally accorded to Newlands in 1887, twenty three years after his article of August 1864.

But there is a final word to be said on this subject. In 1862, two years before Newlands, a French geologist, Emile Béguyer de Chancourtois had already published a periodic system that he arranged in a three-dimensional fashion on the surface of a metal cylinder. He called this the “telluric screw,” from tellos — Greek for the Earth since he was a geologist and since he was classifying the elements of the earth.

Image: Chemistry by macaroni1945. CC BY 2.0 via Flickr.

The post The 150th anniversary of Newlands’ discovery of the periodic system appeared first on OUPblog.

        

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Dmitri Mendeleev believed he was a great scientist and indeed he was. He was not actually recognized as such until his periodic table achieved worldwide diffusion and began to appear in textbooks of general chemistry and in other major publications. When Mendeleev died in February 1907, the periodic table was established well enough to stand on its own and perpetuate his name for upcoming generations of chemists.

The man died, but the myth was born.

Mendeleev as a legendary figure grew with time, aided by his own well-organized promotion of his discovery. Well-versed in foreign languages and with a sort of overwhelming desire to escape his tsar-dominated homeland, he traveled the length and breadth of Europe, attending many conferences in England, Germany, Italy, and central Europe, his only luggage seemingly his periodic table.

Mendeleev had succeeded in creating a new tool that chemists could use as a springboard to new and fascinating discoveries in the fields of theoretical, mineral, and general chemistry. But every coin has two faces, even the periodic table. On the one hand, it lighted the path to the discovery of still missing elements; on the other, it led some unfortunate individuals to fall into the fatal error of announcing the discovery of false or spurious supposed new elements. Even Mendeleev, who considered himself the Newton of the chemical sciences, fell into this trap, announcing the discovery of imaginary elements that presently we know to have been mere self-deception or illusion.

It probably is not well-known that Mendeleev had predicted the existence of a large number of elements, actually more than ten. Their discoveries were sometimes the result of lucky guesses (like the famous cases of gallium, germanium, and scandium), and at other times they were erroneous. Historiography has kindly passed over the latter, forgetting about the long line of imaginary elements that Mendeleev had proposed, among which were two with atomic weights lower than that of hydrogen, newtonium (atomic weight = 0.17) and coronium (Atomic weight = 0.4). He also proposed the existence of six new elements between hydrogen and lithium, whose existence could not but be false.

Mendeleev represented a sort of tormented genius who believed in the universality of his creature and dreaded the possibility that it could be eclipsed by other discoveries. He did not live long enough to see the seed that he had planted become a mighty tree. He fought equally, with fierce indignation, the priority claims of others as well as the advent of new discoveries that appeared to menace his discovery.

In the end, his table was enduring enough to accommodate atomic number, isotopes, radioisotopes, the noble gases, the rare earth elements, the actinides, and the quantum mechanics that endowed it with a theoretical framework, allowing it to appear fresh and modern even after a scientific journey of 145 years.

Image: Nursery of new stars by NASA, Hui Yang University of Illinois. Public domain via Wikimedia Commons.

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By Eric Scerri

After years of lagging behind physics and biology in the popularity stakes, the science of chemistry is staging a big come back, at least in one particular area. Information about the elements and the periodic table has mushroomed in popular culture. Children, movie stars, and countless others upload videos to YouTube of reciting and singing their way through lists of all the elements. Artists and advertisers have latched onto the iconic beauty of the periodic table with its elegant one hundred and eighteen rectangles containing one or two letters to denote each of the elements. T-shirts are constantly devised to spell out some snappy message using just the symbols for elements. If some words cannot quite be spelled out in this way designers just go ahead and invent new element symbols.

Moreover, the academic study of the periodic table has been undergoing a resurgence. In 2012 an International Conference, only the third one on this subject, was held in the historic city of Cuzco in Peru. Recent years have seen many new books and articles on the elements and the periodic table.

Exactly 100 years ago, in 1913, an English physicist, Henry Moseley discovered that the identity of each element was best captured by its atomic number or number of protons. Whereas the older approach had been to arrange the elements in order of increasing atomic weights, the use of Moseley’s atomic number revealed for the first time just how many elements were still missing from the old periodic table. It turned out to be precisely seven of them. Moseley’s discovery also provided a clear-cut method for identifying these missing elements through their spectra produced when any particular element is bombarded with X-ray radiation.

But even though the scientists knew which elements were missing and how to identify them, there were no shortage of priority disputes, claims, and counter-claims, some of which still persist to this day. In 1923 a Hungarian and a Dutchman working in the Niels Bohr Institute for Theoretical Physics discovered hafnium and named it after hafnia, the Latin name for the city of Copenhagen where the Institute is located. The real story, however, lies in the priority dispute that erupted initially between a French chemist Georges Urbain who claimed to have discovered this element, which he named celtium, as far back as 1911 and the team working in Copenhagen. With all the excesses of overt nationalism the British and French press supported the French claim because post-wartime sentiments persisted. The French press claimed, “Sa pue le boche” (It stinks of the Hun). The British press in slightly more restrained though no less chauvinistic terms announced that,

“We adhere to the original word celtium given to it by Urbain as a representative of the great French nation which was loyal to us throughout the war. We do not accept the name which was given it by the Danes who only pocketed the spoils of war.”

The irony was that Denmark had been neutral during the war but was presumably considered guilty by geographical proximity to Germany. Furthermore the French claim turned out to be spurious and the men from Copenhagen won the day and gained the right to name the new element after the city of its discovery.

Why are there so often priority debates in science? Generally speaking scientists have little to gain financially from their scientific discoveries. The one thing that is left to them is their ego and their claim to priority for which they will fight to the last. Another possibility is that women first discovered three or possibly four of the seven elements left to be discovered between the old boundaries of the periodic table (when it was still thought that there were just 92 elements). The three who definitely did discover elements were Lise Meitner, Ida Noddack, and Marguerite Perey from Austria, Germany, and France respectively. This is one of several areas in science where women have excelled, others being observational astronomy, research in radioactivity, and X-ray crystallography to name just a few.

One hundred years after the race began, these human stories spanning the two world wars continue to fascinate and provide new insight in the history of science.

Eric Scerri is a leading philosopher of science specializing in the history and philosophy of the periodic table. He is also the founder and editor in chief of the international journal Foundations of Chemistry and has been a full-time lecturer at UCLA for the past fourteen years where he regularly teaches classes of 350 chemistry students as well as classes in history and philosophy of science. He is the author of A Tale of Seven Elements, The Periodic Table: A Very Short Introduction, and The Periodic Table: Its Story and Its Significance. Read his previous blog posts.

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Image credit: Image by GreatPatton, released under terms of the GNU FDL in July 2003, via Wikimedia Commons.

The post Understanding the history of chemical elements appeared first on OUPblog.

        

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