For centuries, science and stereotypes have been intimately linked. The Periodic Table is a set of stereotypes of how atoms of elements behave; some are more reactive than others, and it is all related to where they exist on the Table. Periodic Table stereotypes are acceptable in science; however, bias against females and under-represented groups in science is not. In 1869, Russian scientist Dmitri Mendeleev discovered the periodic system; however, scientists classified and predicted elements before and after Mendeleev’s framework, and many more worked to find and explain these substances. Females participated effectively in the completion of the Periodic Table as we know nowadays.
Born on 25 February 1896, in Germany, Ida Noddack was one of the pioneering females to study chemistry and obtain a doctorate. She is famous for her discovery of rhenium together with her husband, Walter Noddack, and Otto Berg. They hypothesized that the missing element 75 should have properties similar to its horizontal neighbors—molybdenum not manganese—which was the common belief at the time.
In June 1925, the team of three scientists discovered rhenium and named it in honor of the Rhine River. This new element filled one of the two spots that were vacant at that time in the Periodic Table below manganese. Rhenium is one of the rarest elements in the Earth’s crust and can be found today in metal alloys that are used to build jet engines.
The team also tried to fill the other vacant spot above rhenium; they claimed they have discovered it, but the experimental outcomes were not fruitful and the findings were dismissed. Despite this disappointment, Noddack continued focusing on chemistry; she challenged a widely-believed theory by Enrico Fermi at that time, arguing that elements could be broken down into smaller fragments, but the argument lacked experimental proof. Yet, with time, her arguments were proven correct and the concept she proposed later became known as nuclear fission; Noddack is acknowledged as the founder of this branch of chemistry.
Following Ida’s footsteps in the nuclear fusion experimentation, Austrian physicist Lise Meitner was part of the team who examined the experimental data found earlier on nuclear fusion; her reasoning and calculations helped in forming the theory of nuclear fission as we know it today. She and her team proved by experiment that the atomic nucleus could be split into smaller nuclei and these findings were published in 1939, regretfully without Meitner’s name on the paper.
In 1944, the team’s work was awarded the Nobel Prize in Chemistry; surprisingly, the sole recipient, Otto Hahn, did not mention Meitner’s contribution to the discovery, even though her calculations were the reason behind discovering the phenomena. In honor of her contribution to radioactive science, a later-discovered element was named meitnerium after her.
In 1897, Marie Curie was exploring radioactivity for her PhD on uranium rays; she was not aware that her studies will lead to the discovery of a new element in the Periodic Table. She discovered an ore with a very strong radioactivity that she could not explain by uranium alone. The discovery made her suspect the presence of other elements; she asked the assistance of her husband and together they identified spectroscopic lines of two new elements: radium and polonium. They spent more than three years to grind, dissolve, boil, filter, and crystallize tones of the mineral to extract just 0.1 gram of radium compound.
In 1911, Marie Curie won the Nobel Prize for discovering polonium and radium, and for the isolation and study of radium. Nowadays, polonium is used to power many space crafts and rovers sent on exploration missions in outer space. When the element decays, its temperature reaches around 500°C; it acts as an energy source for space technology. As a result of her contributions in the field of chemistry and to honor her legacy, scientists named another radioactive element that was discovered years after her passing curium.
When the Periodic Table was primarily proposed in 1869, Mendeleev left gaps for the elements that were not discovered yet, but predicted to exist. Marguerite Perey’s filled one of them in 1939 with a new radioactive element that she named francium after her home country, France. The lifespans of radioactive elements are difficult to determine, since they are so unstable and the process is random. Instead, scientists can estimate the half-life of an element, which is the time taken for the radioactivity of an element to have decreased to half its original value. Francium is so intensely radioactive that its half-life is only 22 minutes.
Francium is the only element that was discovered solely by a female scientist without the assistance of any male. Perey was also the first female to become the Chair of Nuclear Chemistry at the University of Strasbourg and the first female to be elected as a corresponding member of the French Academy of Sciences. Sadly, like others working with radioactive elements before her, she died of radiation-related causes.
Female contributions to chemistry and to the Periodic Table are not restricted to past centuries only; their research and experimentation continues to amaze the scientific community. In 2016, chemist Dawn Shaughnessy and her California-based team, in collaboration with the Joint Institute for Nuclear Research in Dubna in Russia, discovered three new elements in the Periodic Table with atomic numbers 115, 117, and 118. The three elements were classified as “super heavy”, and they were created through using particle accelerators to shoot beams of nuclei at other, heavier, target nuclei.
Shaughnessy benefited from the technological advances in electronics and detectors during her experiments; she stated that, without these technologies, her experiments would have not been completed. Some of the newly–discovered “super heavy” elements exist for less than a thousandth of a second; “a new element is created by fusing two lighter elements together,” she explains. “We do not see the actual element, because it is too short-lived but we do see its radioactive decay particles and can then link those back to the original element we created.”
Shaughnessy, became interested in chemistry in high school and received both a BSc and PhD in nuclear chemistry from University of California, Berkeley. Currently, she is the Principal Investigator at Lawrence Livermore National Laboratory.
Females showed deep interest in chemistry throughout history. Though historically discriminated against and marginalized, they are deeply rooted in every scientific field even when their contributions are made invisible by terms like “and colleagues” or “and co-workers”. During this celebratory year of the Periodic Table, let us remember and celebrate the female scientists who contributed to shaping it and discovering the elements that we all, men and women, benefit from. It is crucial to acknowledge the contributions of all scientists regardless of their gender or any other discriminating factor; this is the only way towards a better and sustainable future.
References
ansnuclearcafe.org
bigthink.com
iupac.org
nature.com
physicsworld.com
sciencehistory.org
shethoughtit.ilcml.com
thenakedscientists.com
verilymag.com
Published in SCIplanet, Spring 2019 issue.