10 Greatest Discoveries in Chemistry

Table of ElementsThroughout history, many great discoveries have been made either by accident or someone searching for the way that something works. Some of these discoveries are more important than others, but they are all important nonetheless. Some are in the field of chemistry while others have a basis in chemistry and they also combine ideas from physics and other sciences.

Periodic Table of the Elements

The periodic table of the elements is one of the most important developments in the history of the field of chemistry. The periodic table consists of all of the chemical elements that are known and they are arranged and organized on the table according to their electron configurations, atomic numbers, and their recurring chemical properties. The order in which the elements are presented on the table correspond to their atomic number.

The person who first published the periodic table of the elements was Dmitri Mendeleev, a Russian chemist. He developed the table based on his findings and the findings of other chemists, including John Newlands and Antoine-Laurent de Lavoisier. Newlands published a work entitled the Law of Octaves in 1865. This work discussed the periodicity of the known elements of the time according to their atomic weight. In his work, he also made a proposal that helped identify the potential for elements, including germanium. However, the Society of Chemists did not recognize or endorse his idea until more than two decades later.

Mendeleev published a two-volume work entitled Principles of Chemistry between 1868 and 1870, after he became a teacher. This work because the ultimate textbook regarding chemistry and the elements. In the book, he strived use a chemical’s properties in order to classify them in a simple table.


While oxygen has always existed since before mankind was even on the earth, discovering the nature of oxygen and its elements was a huge accomplishment in the history of chemistry. Joseph Priestley is the scientist who is credited with discovering oxygen in 1774, but Antoine Lavoisier gets the credit for discovering the element that oxygen is made from.

However, there is some controversy over who was actually the first person to discover this all-important element. In 1772, a Swedish chemist by the name of Carl Wilhelm Scheele made the same discovery that Priestley made. Unfortunately, he didn’t officially publish his findings until 1777, which was five years after his discovery.

Priestley conducted several experiments to help understand the nature of oxygen better. He experimented with its role in respiration and in combustion. He also used oxygen in an experiment in which he dissolved fixed air in water. This created carbonated water, but he called it “dephlogisticated air.”

While Priestley experimented with oxygen and found out much about it, it was Lavoisier who actually gave the element its name. He also accurately described how it plays a role in combustion. In addition, he worked with others to help come up with oxygen’s chemical nomenclature.


ElectronsElectrons are negatively charged particles, but that was unknown for many years. Scientists knew about electricity and worked with it for many years before they understood that its current was actually composed of electrons. Many scientists worked with cathode tubes which created streams of electricity, but they were not sure how it actually worked.

Some thought that the cathode rays were actually streams of particles. Others thought the rays traveled through a mysterious “ether.” It wasn’t until 1897 when JJ Thomson decided to find out what exactly was going on with electric currents. Thomson, who taught physics at the UK’s Cambridge University, placed cathode tubes in magnetic and electric fields. He knew that the fields moved particles from one side to another, but they did not have an effect on how the waves actually move.

During his experiments, he found that the cathode rays bend over to one side. As a result, he determined that cathode rays must be made of small particles, which he termed “corpuscles.” At first, he thought these small particles were too small for anybody to care about. However, he found out that electric currents were composed of moving electrons. And since most of the products that people use these days are operated by electricity, the electron became one of the most important discoveries in chemistry and physics.


One of the most popular and most widely used psychedelic drugs during the 1960s was LSD. It is still used today by people who like to go on psychedelic “trips” from time to time. But LSD was not invented as a way for people to get high. In fact, its psychedelic properties were not even discovered until five years later.

Swiss chemist Albert Hoffman is credited with being the first to synthesize LSD on November 16, 1938 while working in Switzerland at the Sandoz Laboratories. At the time, he was part of a much larger research program that was looking for alkaloid derivatives. They had been researching ergot, which is a fungus that is found in some types of tainted breads and had been used for medicinal purposes for decades. When it is in its natural form, ergot is a fatal poison that caused hundreds of thousands of deaths over the centuries. But it wasn’t until the late 17th century when ergot was believed to be the cause of the numerous deaths.

When administered in small doses, however, ergot could be used to constrict blood vessels and help with childbirth. Part of the problem was isolating the useful properties of this fungus to prevent other unwanted reactions. This is what Hoffman’s team was working on at Sandoz.

Five years after it was first synthesized, Hofmann decided to work on it some more. While he was re-synthesizing it in order to extend the study of it, he grew dizzy and had to take a break from working on it. He wrote in his journal  that he had to go back home where he then felt dizzy and restless. He also described feeling as though he was in an intoxicated state with a highly stimulated imagination. It was almost dreamlike, as he wrote in his journal. He described seen amazing pictures and intense colors in a kaleidoscope fashion. In all, Hofmann said the experience lasted for about two hours before it began to fade away.

Atomic Theory

John-DaltonIn 1808, John Dalton discovered a way to link invisible atoms together to things that had measurable qualities, such as a mineral’s mass or the volume of a certain gas. In his theory, he stated that elements consist of small microscopic particles that are called atoms. His theory went on to state that a pure element only consists of identical atoms that have the same mass.

Dalton wasn’t the first person to believe that all life was made up of tiny particles called atoms, though. This idea originated to the 5th century in Greece when Leucippus of Miletus, a Greek philosopher of the time, and his student Democritus believed that atoms were too small to be seen. Their theory went on to say that atoms were solid and did not have any internal structure. They also believed that taste, color and other qualities were made up of atoms.

Aristotle did not agree with the theory that everything was made up of small particles. And since he was such an influential person of his time and even beyond his time, the philosophy of an atomic theory was largely dismissed for several centuries.

Dalton gave credibility to the idea of the atomic theory when he published A New System of Chemical Philosophy. His theory was based on four ides. The first is that atoms composed chemical elements. The second is that the atoms in an element had the exact same weight. Third, the atoms in different elements had varying weights. And finally, atoms only combined in small ratios of whole numbers in order to form compounds. The Greeks had many of these ideas and Dalton built on them. His main contribution to the theory was a way to determine an elements atomic weight. In 1805, he published an essay which included the atomic weights for more than 20 elements. In addition, Dalton is also credited with being the first person to provide standard symbols for recognizing the elements.

Smallpox Vaccine

The smallpox vaccine may have been one of the most important chemistry discoveries in the history of mankind. Smallpox was a condition that was running rampant throughout the West and in Europe during the 17th and 18th centuries. There would be epidemics periodically and these epidemics would wipe out a huge portion of the population. In some cases, it killed as many as 35 percent of the people who became infected with it. Most of those who survived smallpox had scars and problems for the rest of their lives after the infection. It affected everybody – those who were poor and even those who were wealthy. However, the eastern countries were dealing with smallpox very effectively and they had prevented the disease for several centuries. Places like China, the Middle East and even Africa had a method for preventing smallpox that was soon introduced to the West.

Lady Mary Wortley  Montagu gets credit for raising awareness of the rest of the world’s method for dealing with smallpox. She was a member of the British nobility and she lived in Turkey during the time her husband, a British ambassador, was stationed there. She contracted smallpox in 1715 but survived. However, the disease had taken its toll on her physical appearance, causing her face to be misshapen and extremely scarred. She didn’t want her kid to go through the same thing so she was very interested when she heard that the Turks had a way to prevent this illness.

The idea that other parts of the world used for preventing smallpox was inoculation. This is where very small particles of the disease was given to a person, either inhaled through their nose or through an opening on their skin. The person then experienced a mild case of the disease, but their body would build up an immunity to it so they would be immune to it forever.
Lady Mary Montagu
Lady Mary advocated for inoculation when she returned to England in 1721. She had her own two children inoculated with smallpox and they survived without any lifetime effects. Many people brought their children to be inoculated and even the Royal Family had their children inoculated, only after the condition that six prisoners would be inoculated first. All prisoners survived the inoculation and were given a pardon on the remainder of their sentences.

Although Lady Mary brought the idea to the West, Edward Jenner is the one credited with discovering and developing the modern vaccine for smallpox. Using information from studies on the cowpox virus, which is similar to smallpox, he was able to make a vaccine that was safer to use for humans. In fact, the word “vaccine” is actually derived from the Latin word “vaca,” which means cow. He did many experiments with his cowpox vaccine and in 1796, he presented his data to the Royal Society. Jenner was able to reduce the death rate from smallpox from a high mortality rate down to almost zero.

In the 1970s, it was announced that the smallpox vaccine had essentially been eradicated. There are still two samples of the original virus – one at the State Research Center of Virology and Biotechnology in Koltsovo, Russia, and one at the CDC in Atlanta, Georgia. They are kept around mainly for research purposes, but also in case there is a new outbreak and these samples are needed to create a new vaccine.


In the 1890s and early 1900s, Marie and Pierre Curie worked with uranium ore, extracting the uranium from it and experimenting with it and studying it. As a result, they discovered and were able to isolate radioactive materials. Marie found that the residual materials from the uranium were actually more active than pure uranium.

The Curies were building on earlier findings that were discovered by Antoine Henri Becquerel in 1896. He was a French scientist who was doing experiments on exposing uranium-bearing crystal to the sunlight. After sitting the uranium in the sun and then placing it on a photographic plate, there was an image on the plate. He put the uranium in a drawer for a few days because the weather was cloudy and sunlight experiments were not possible. When he came back to the uranium a few days later, he found that it had left an image even though there was no light. This was radioactivity, but it was the Curies who coined the term following their experiments with spontaneous emissions.

In 1903, the Curies and Becquerel shared the Nobel Prize in physics for their work in discovering radioactivity. Marie Curie won another Nobel Prize in 1911 for discovering radium and polonium, becoming the only person to win two Nobel Prizes.


Louis PasteurThe process of pasteurization has been called one of the most important discoveries in science and chemistry because of the numerous lives that it has saved through preventing disease. Discovered by French scientist Louis Pasteur in the 1800s, pasteurization was a method by which milk was heated to a high temperature and then cooled down quickly before it was bottled. This helped the milk stay fresh for a long period of time.

But this method has been used in the food and drink industry since then for many other things because it helps delay the spoilage process that is caused by the growth of microbes in food and drinks. In France, he applied his research and findings to the wine and beer industry, saving them from certain collapse that was coming from the problems of production and contamination.

In 1863, Napoleon III commissioned Pasteur to study wine contamination. He found that the contamination was caused by microbes and he began heating the wine to temperatures between 120 and 140 degrees Fahrenheit, which killed the microbes. This was called pasteurization.


Roy Plunkett accidentally invented Teflon, the non-stick substance that most cookware uses these days, in 1938 while working at Kinetic Chemicals. He was working on creating a new CFC refrigerant at the time. But during his experiments using a pressurized storage container, he found that the iron from the inside of the container he was using actually acted as a catalyst.

Nearly 20 years later, a French engineer by the name of Marc Gregoire used Plunkett’s findings and coated a cooking pan for the first time with the Teflon resin. The brand was called Tefal.

Teflon is one of the most slippery materials known today and it is inert to almost all chemicals. It was first marketed in 1945 under the Dupont company. Its molecular weight can be more than 30,000,000, which means that it is one of the largest molecules known to be in existence. It is a colorless and odorless power that has revolutionized the cooking industry by making non-stick pans and pots available to the average consumer. But it also has a much wider range of uses for industrial purposes and household purposes.


The discovery of penicillin is credited to Alexander Fleming, a Scottish scientist and Nobel Prize winner in 1928. Fleming found that growing Penicillium rubens created a property that could be used as an antibiotic. He named this discovery penicillin.

Felming’s discovery almost did not happen though. In fact, it was almost thrown away in the trash. He was studying a Petri dish that had already been discarded when he found that the mold in the dish actually contained a powerful antibiotic. At the time of the discovery, Fleming was working at St. Mary’s Hospital. He had just returned from a family vacation when he was going through the Petri dishes that he left aside for another scientist to use while he was gone.

Alexander FlemingFleming was sorting through the Petri dishes and putting the contaminated ones in a tray that was filled with Lysol. When his former lab assistant, Merlin Pryce, came by to talk to Fleming, Fleming began talking about all of the added work that he was doing lately. He began going through his stack of Petri dishes, some that were not submerged in the Lysol. When he picked up one of the dishes to show Pryce, he noticed that there was a mold in the dish that had killed the staphylococcus bacteria that was growing in there. It was at this point that he realized he may be on to something.

Fleming spent the next few weeks doing experiments and trying to single out the substance in the mold that had killed the bacteria. He discussed his finding with a mold expert – C.J. La Touche – who worked in the same building. That is when they reached the conclusion that the mold had to be a penicillium mold. They also speculated that the mold had possibly floated up to Fleming’s lab from La Touche’s lab, which was located directly beneath Fleming’s. During his further experiments, Fleming found that the new mold he had discovered was non-toxic. He published his findings in 1929, but there was not a great acceptance of what he found.

While he did discover this antibiotic, it wasn’t until nearly a decade later when someone was able to turn this discovery into the drug that it was become today.

With Fleming’s discovery of penicillin erupted a strong interest in the field and study of antibiotics in the modern era. And although Fleming gets the credit for discovering this antibiotic property, it wasn’t until more than a decade later when Howard Walter Florey, an Australian Nobel Prize winner, along with Ernst Chain and Norman Heatley developed penicillin as a medicine while working at Oxford University during World War II. They isolated the substance that had bacteria-killing properties and turned it into a brown powder. Once they found that it was safe to use, they mass produced it so it could be available to the soldiers during the war. It saved hundreds if not thousands of lives of soldiers who would have died of an infection otherwise. It was used and is still used to treat problems like pneumonia, syphilis, gangrene and much more.