Wednesday, April 6, 2016

Dmitri Mendeleev, the Periodic Table, and a Bold Prediction

What is the stereotypical image of science? Beakers? An atom? How about the periodic table?

I would hazard a guess that every science classroom and laboratory in the country has at least one Periodic Table of the Elements in it. This seemingly simple table, full of elements as common as helium or gold and as rare as gallium or mendelevium, is actually an incredibly complex and important piece of information: the basis of chemistry, biology, and in many ways, science itself.
The Periodic Table of the Elements
But where did it come from? How did this table full of elements come to be? How was it organized? Who determined that hydrogen comes before magnesium, which comes before silver? And how?

Today, we will be exploring the history of the periodic table, especially as it relates to the man who is given the bulk of the credit for it's discovery, the Russian polymath and chemist Dmitri Mendeleev.
Dmitri Ivanovich Mendeleev

Siberia to Saint Petersburg

Dmitri Ivanovich Mendeleev was born in 1834 in Verkhnie Aremzyani, in the Russian province of Siberia. He was the son of a Russian teacher and factory owner, Ivan, and his wife Maria, and he was the youngest of as many as sixteen children. The year Dmitri was born, his father went blind, ending his teaching career. Dmitri's mother then reopened a glass factory his father had once operated, to support the family. At the tender age of thirteen, Dmitri's father, Ivan passed away. At fifteen, tragedy struck again: the glass factory burned to the ground, leaving the Mendeleev family without a source of income. Dmitri was Maria's brightest child, the one most likely to follow his father's path and become a teacher and scholar. Because Dmitri was the youngest, and his siblings had all moved out of the house, Dmitri's mother made a drastic decision.
Dmitri's birth place in Siberia, Russia.
Maria Mendeleeva took Dmitri, her most promising son, to Russia's major universities, trying to get him a formal education so he could teach like his father. Mother and son rode by horseback from far Eastern Russia across the frozen tundra and the massive Ural Mountains which divide Europe from Asia, more than 1,400 miles to the great city of Moscow. The pair went to Moscow University and asked for admission, but Dmitri was promptly rejected. So Mendeleev mother and son continued on, still on horseback, another 400 miles to the Russian capital of St. Petersburg, where they went to St. Petersburg's Main Pedagogical Institute- his father's alma mater- to ask for a place to study. Finally, after 1,800 miles Dmitri Mendeleev was accepted and given a place to study. One last tragedy struck- his mother, her mission complete, promptly dropped dead. Despite this, Dmitri studied and trained to be a teacher and a chemist. In 1856, at the age of 22, he was awarded a Masters degree in chemistry, and chemistry would never be the same.
Dmitri's (and his fathers) alma mater, St. Petersburg University.
The Ural Mountains, which the Mendeleev's had to cross to reach St. Petersburg.
In 1859, Mendeleev traveled to Heidelburg, Germany, where he researched under notable chemists like Robert Bunsen (creator of the Bunsen burner, every high schooler's favorite chemistry tool). In 1860, Mendeleev experienced another life-changing event: while still in Germany, he attended the first-ever international chemistry conference. Among the decisions made at this congress which impacted both chemistry and Mendeleev's thinking were:
Chemist, inventor and Mendeleev mentor Robert Bunsen.
Bunsen's most famous, and popular, invention, the bunsen burner.
  • The conference determined a standardized way to determine the atomic weight of various elements. The periodic table Mendeleev eventually created was based on (accurate) atomic weights of elements, so this development was key.
    How to read the Periodic Table.
  • The conference also had many discussions on the laws and nature of gases, which would become another of Mendeleev's scientific passions.
Soon after the conference, Mendeleev returned to St. Petersburg and resumed teaching chemistry at his alma mater. He quickly realized that the quality of Russian chemistry and students was nowhere near what he had experienced in Germany. Mendeleev believed one of the biggest issues was the lack of Russian language textbooks, especially in chemistry. So in 1861, at the age of 27, Mendeleev managed to produce a 500-page textbook, Organic Chemistry, in less than three months! This book would make Mendeleev a (relatively) wealthy man, but more importantly, it built up his reputation in the Russian and world chemistry communities, which would help his theories about the elements to spread more easily later. By the age of 33, he was the head of the chemistry department at St. Petersburg University,  and by 35 he would write another world-acclaimed chemistry textbook.

The Periodic Table of Elements

All of those early accomplishments would pale in comparison to his next obsession. Dmitri Mendeleev, while working on his second textbook, began to obsess with a way to organize the roughly sixty elements known to science at the time in a way that made sense. Mendeleev was certainly not the only scientist working on a way to organize the elements at the time. Other scientists had created their own tables that grouped the elements according to various characteristics and patterns.  But Mendeleev certainly has the most famous and well-recognized method today. How did he get this Periodic Table?
An early published edition of Mendeleev's charts. Note the gaps he left for undiscovered elements.

Dmitri Mendeleev, as discussed earlier, had locked his attention on the atomic weight of elements. He had noticed that if you laid out the elements by their atomic weights then a rough pattern began to emerge. But Mendeleev could not figure out just what that pattern was. Whatever the pattern, it did not seem to have any logical organization, and for a bright mind like Mendeleev's this was like torture. Mendeleev obsessed over this problem. Legend has it that he wrote out all of the elements (roughly 60 were known at the time) on cards, with all of the known information about them, and began arranging the cards over and over by different methods, trying to discover a logical pattern. He allegedly worked on this for hours, even days, trying to find a pattern. Eventually he came to a realization- the problem was not that he was not seeing the pattern in the cards. The problem was that he was missing some! Mendeleev knew about roughly 60 elements. Today we know of 118. So the reason Mendeleev could not find a pattern at the beginning of his research was that he had gaps in his chart that he was not aware of!
Mendeleev hard at work on his Table.

Once Mendeleev had cleared this mental hurdle, he was well on his way to creating the periodic table we know today. By placing blank cards (or spaces) in his periodic table, he was able to come up with a logical pattern for the atomic weights of the elements. What he discovered is the reason why it is called the periodic table: there are periodic, repeating patterns in the elements that make it possible to place those elements into columns and rows that share similar traits. Mendeleev realized that every seven elements (in reality it was eight but the non-reactive Noble gases had not been discovered yet) the pattern would start over. This is why the periodic table has eight columns of elements. Within the original table that Mendeleev created (he constantly tinkered with it, reorganizing it to make it more efficient), there were blank spaces for the elements that had not yet been discovered, but which Mendeleev would famously predict and describe.
The patterns which exist in the Periodic Table.

As I said before, Mendeleev's table was not the only one created, and his style of organizing was not the only way people set up the periodic table. At least six other scientists published periodic charts at around the same time, but Mendeleev's set-up was much easier to print than other proposals, such as a screw-shaped periodic table or a globe, neither of which fits in a textbook very easily. This does not mean that the table we have today is the only way to represent the elements in an orderly fashion- even the table we use today has issues. There should be no separated two rows of elements at the bottom of the chart, and ideally, the chart would be able to wrap around so that the first and eighth columns are next to each other. But so far, the famous periodic table is the one that we recognize because it is the best, easiest representation we have available to us.
This and the following pictures are some of the other ways which the elements can be logically displayed to show a pattern.

Bold Predictions

Dmitri Mendeleev's research and periodic table alone are enough to make him one of the greatest scientists of all time. But what he did next with his knowledge makes him a legend. Remember those blank spaces in his periodic table? The ones that he placed there because he said the elements that belonged there had not yet been discovered? Well, he began predicting the details of those elements. And he was not predicting basic things like weight. Dmitri predicted what the elements would look like, how they would behave, and a number of other "facts" that he was sure would be true if and when those elements were discovered.

Mendeleev ultimately predicted the discovery and characteristics of eight additional elements, the three most notable of which he called eka-aluminum, eka-boron, and eka-silicon (eka is Sanskrit for "one," and each of these elements was proposed to be one spot after the element in it's name). But making a prediction does not make you a great scientist. A lot of people have made a lot of predictions throughout history, and only a small number have been true. What makes a great scientist is when you make a prediction and it comes true. And during his lifetime, three of his predictions would be discovered.
Gallium, AKA eka-aluminum, Mendeleev's first predicted element to be discovered.

The first of Mendeleev's elements to be predicted was eka-aluminum. In 1875 the French chemist Paul Emile Lecoq de Boisbaudran discovered a new element which he named gallium, after "Gaul," the Roman name for France. It turned out that this element was Mendeleev's predicted eka-aluminum. But when Mendeleev received de Boisbaudran's study of the new element, Mendeleev was sure that de Boisbaudran had made a serious mistake. When Mendeelev had made his prediction about the traits of this "gallium," he had predicted that the element's density would be around six grams per centimeter cubed, while the Frenchman's predictions said that it's density was only 4.9 grams per centimeter. Not only that, but de Boisbaudran had the audacity to claim that he had discovered gallium- which could not be true, because Mendeleev had predicted the element-in his head- nearly a decade before. Dmitri quickly published a journal article claiming that he, not de Boisbaudran, had discovered the element, and that the data de Boisbaudran had measured was incorrect. In summary, Mendeleev was claiming to know gallium, which he had predicted but never actually observed, better than the man who had actually discovered it. That was how sure he was of his own mind and the patterns he had discovered about the elements.
Paul Emile Lecoq de Boisbaudran, who tried to claim he had discovered gallium.

The crazy part about this story, though, is that Dmitri Mendeleev was correct. de Boisbaudran had incorrectly measured gallium, and it was much closer to Mendeleev's prediction that de Boisbaudran's published number. Having never examined the actual element, Mendeleev knew more about it than de Boisbaudran. Mendeleev's correct predictions are what make him such an amazing scientist. Within ten years, two of his other predictions would be discovered as well. In 1879 Mendeleev's eka-boron would be discovered and called "scandium." In 1886 eka-silicon was discovered and named "germanium." One last interesting fact: all three of these elements that Mendeleev predicted would be discovered in his lifetime, and all three, in one of history's strange twists, would be named after the home countries- France (Gaul), Scandinavia, and Germany- of the scientists that discovered each of them. That has nothing to do with Mendeleev, but it is still coincidentally interesting.
Scandium, AKA eka-boron.
Germanium, AKA eka-silicon.

Only One Mendeleev

Now I have a few short anecdotes that come from Mendeleev's personal life and other endeavors. First is a story about Mendeleev's marriages. He had two in his life. He married his first wife, Feozva, in 1862. While their marriage started out relatively happy, and produced two children, by the late 1860s they were no longer living together, although they did not get a divorce. The unhappy couple would switch places with each other between their two homes when Mendeleev needed to be in St. Petersburg. For nearly a decade this living situation worked for the couple and they were still "married." But this became impossible in 1877, when Mendeleev met a young student, Anna Popova, whom he became obsessed with.

Anna Popova lived with Dmitri Mendeleev's sister, Ekaterina, while she was studying art at a local university. A year later, Ekaterina moved in with her younger brother, taking Anna with her. Mendeleev began to act in a way that can only be described as creepy. Despite being 43, while Anna was only 17, he began to write her secret love letters, helping her to carry her supplies to school, and even having weekly salons with various artists, which he admitted later he had done to help Anna's career, not his own.
The young Anna Poplova.
Soon people around Mendeleev's university became aware of the situation, and tongues began to wag about what was happening. Trying to save her brother's reputation, Ekaterina moved her family out of Dmitri's house, but this did not stop him. In 1879 he proposed to her and was rejected, and her father visited St. Petersburg to make Dmitri stop, finally sending her to Italy in 1880. A devastated Dmitri considered suicide,  and wrote a will giving all of his possessions to Anna. In 1881 he visited Italy again, proposing and telling her he would kill himself if she did not accept. Fortunately for Dmitri, she accepted this time.
One of many Russian Orthodox Churches.
There was one last barrier to Dmitri's dream marriage, however. He was still legally married to Feozva, and the Russian Orthodox Church did not regularly grant divorces. However, Feozva asked for a divorce on the grounds of adultery (Dmitri had tried to have an affair with a maid early in their marriage, and it was relatively well known that Anna was pregnant). In February 1882, his first marriage was officially dissolved. But his problems with divorce were not over. According to the church, he would have to wait seven years before remarrying, or else he would be considered a bigamist. He solved this problem by bribing a local church official 10,000 rubles (the official later lost his position), who married Dmitri and Anna in January 1882, before Dmitri's first marriage was officially dissolved. Their child was born in December of 1881, but the birth certificate was dated to March of 1882, to try and salvage some respect for their marriage.
Ivan and Anna are in the lower left corner of this picture.
Throughout the 1880s, Mendeleev was considered a bigamist by public opinion. Officially, however, this was ignored by the church and the government, almost certainly because of Mendeleev's scientific reputation and achievements. A few years later, when a high-ranking government official asked Tsar Alexander III to allow a similar divorce and immediate re-marriage, he was denied. When the official brought up the Mendeleev precedent, the Tsar allegedly replied, "Mendeleev has two wives, but I have only one Mendeleev."
Tsar Alexander III, who only had one Mendeleev.

Creator of Vodka?

Dmitri Mendeleev is often cited, erroneously, as the person who determined that vodka had to be 40% alcohol, in a sense "creating" modern vodka. This myth comes from the fact that in 1892 he was named the Director of the Bureau for Weights and Measures, and as such was allegedly in charge of deciding what percentage Russian vodka had to be. This belief has even been used for marketing of one of Russia's largest vodka distillers, Russian Standard:
In 1894, Dmitri Mendeleev, the greatest scientist in all Russia, received the decree to set the Imperial quality standard for Russian vodka and the 'Russian Standard' was born.
Russian Standard Vodka
While this claim is certainly an ingenious marketing technique, it is not true. In reality, the director position Dmitri held would never have had the responsibility of determining production standards for Russian distillers, and Mendeleev certainly never made a determination about the quality of Russian vodka. The standard 40% alcohol content for vodka, which is a defining factor for vodka today, was actually put in place in 1843, when Mendeleev would have been only nine years old! So while it is an interesting story, it almost certainly has no basis in truth.
You can see at the bottom of the bottle the 40% alcohol by volume label, which Dmitri Mendeleev did not mandate but which makes vodka vodka.


Dmitri Mendeleev may have been one of the most talented, multi-faceted scientists of all time. I did not have time to go into all of the different things he did beyond creating the basis of modern chemistry. Books like A Well Ordered Thing by Michael Gordon, among others, do an excellent job of digging into Mendeleev's work, among other things, of studying the nature of gases, debunking mysticism and the 1800s spiritualism movement, working to standardize the Russian weights and measures system, and many other interests as well. He may have also been one of the creepiest pursuers of a love interest of all time. He revolutionized the way scientists conduct chemistry today, and the way even young students study science and the elements. Without his discovery, who knows how far behind science would be today.
A rather creepy photo of Mendeleev.
During his life, Dmitri Mendeleev was viewed as a talented, revolutionary but troubled and difficult personality to deal with. Today, many of his personal deficits have been overlooked in favor of the genius it required to come up with his crowning achievement, the Periodic Table of the Elements. Dmitri Mendeleev is still seen as a treasure of Russia, as evidenced by his use in the Russian vodka advertisement above. A statue of him still sits in front the Bureau of Weights and Measures in St. Petersburg, surviving even the Communist period's purges of Tsar-era Russian history. Many cities in Russia still have a Mendeleev Street in them.
A statue of Dmitri Mendeleev in front of his alma mater. Notice the periodic table in the background.

Perhaps the greatest tribute to Dmitri Mendeleev, however, is the 101st element in his own table. In 1955, a team of American scientists at the University of California, Berkeley, bombarded an element called einsteinium with atoms of hydrogen at high speed inside of a nuclear cyclotron, trying to increase the atomic number of the einsteinium and create a new, synthetic element. After nearly a year of experiments and preparation, they conducted their experiment. What they created was a new, radioactive metalloid, only the ninth kind of element to be produced solely in a lab. This new
The cylotron in which mendelevium was originally created.
element, even to this day, is impossible to make in large quantities, so very little is known about it's appearance or physical properties, and it has no current uses outside of scientific research. When it was first created, it also lacked a name, but it's creators quickly solved that. Because of Mendeleev's contributions to chemistry in general, and the fact that the scientists had used his methods of predicting an element's characteristics to aid their research, they decided that the name should be a tribute to Dmitri. Despite being in the middle of the Cold War with Mendeleev's home country, these American scientists decided to name their new element mendelevium in his honor. And so for the rest of scientific history, Dmitri Ivanovich Mendeleev will be enshrined in his own crowning achievement, a scientific Hall of Achievement that contains such other notable scientists as Einstein(ium), Copernic(ium)us, Curi(um)e, and Nobel(ium). It is a fitting tribute.
Another scientist enshrined in the Periodic Table as an element.
Dmitri Mendeleev's last, and most fitting, tribute.


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