Chemistry is an ever-changing field. Theories are constantly being revised and rewritten because new information has become available or a new discovery has been made. Without the founding forefathers of chemistry: Aristotle, Lavoisier, John Dalton, and others, modern chemists would be at a complete loss. Chemistry is a collaborative effort between the work of those scientists that have existed before and those that exist now.
The discovery of the composition of the atom and the discovery of radiation and radioactivity go hand in hand. In 1803 Dalton established atomic theory and substantially proved that matter consists of small, indiscrete particles. Radioactivity demonstrated that this atom was neither indivisible nor immutable.
Madame Marie Curie was one of the first pioneers of radiation. Born in 1867, she discovered the elements radium and polonium. It is also from her work that we have definitions of radiation and radioactivity. Radiation is defined as the emission and propagation of energy in the form of waves or rays. Radioactivity is defined as a stream of particles or electromagnetic waves emitted by the atoms and molecules of certain substances as a result of decay.
The next pioneer of radiation was Wilhelm Röhtgen. He discovered x-rays in 1895. He was able to see that swiping radium on a glass plate produced a glow. When he put his hand on the plate he was shocked to find he could see his bones. This discovery would later morph into our modern day x-ray machine.
The third pioneer of radiation was Henri Becquerel. In 1909 He proved that beta rays are just fast electrons shooting themselves out of radioactive material. Together, these three scientists amassed enough information about radiation between them to carry us into the modern world.
Parallel to the discoveries on radiation were the discoveries on the composition of the atom. The discovery of the atom’s true form was one that took many years and the hypothesis of several people to get right. JJ Thompson discovered the electron in 1879 and proposed the Plum Pudding Model of the atom in 1904. His model showed electrons, neutrons, and protons simply floating around in a sphere with no semblance of order to them. This theory prevailed until the work of scientists Neil Bohr and Ernest Rutherford disproved the plum pudding model.
Ernest Rutherford, inspired by Sir JJ Thompson began his work on the atom with Neil Bohr. The two were positive that there was more to the atom than simply floating particles. They believed that the atom had some structure to it. In order to prove this theory, Rutherford created the gold foil experiment. The gold foil experiment was conducted as follows: a beam of alpha particles was shot at a sheet of gold foil. A circular fluorescent screen was placed around the foil as to see where particles landed. While most particles hit the screen at random, some were deflected to the sides. This proved that a tiny, dense nucleus was causing these deflections. The gold foil experiment helped Rutherford establish nuclear theory and substantialize the Rutherford-Bohr model of the atom. The Rutherford-Bohr model was created in 1913 and illustrated that electrons were in a fixed rotation around the nucleus. These electrons can move up or down a valence shell if enough pressure is put on them. The Rutherford- Bohr model disproved the plum pudding model of nine years before. Sir JJ Thomson created the plum pudding model when the nucleus had not been discovered yet. His work pioneered the structure of the atom. Rutherford and Bohr furthered Thompson’s methods and discovered something he hadn’t: the nucleus. As a result, their model was more correct. Even though the Bohr model is still used to this day it is technically not correct. In actuality, the most accurate model of the atom is the cloud model. This model has the nucleus in the middle with free-floating electrons. This model is composed mostly of free space. In hindsight- the physicality of Thompson’s model was somewhat correct but it lacked the components of the Bohr model. Only from both models and those who created them can we result in the most accurate cloud model.
Chemical warfare is the combination of knowledge of the atom and knowledge of radiation. Both elements are integral to chemical warfare, especially in the future and in the World Wars. In order to understand chemical warfare currently, we must understand its history. Chemicals have been used in warfare as early as 600 BCE with the Athenians. The Athenians pioneered chemical warfare by using poisoned water against their enemies. Prior to WWI, warfare was done in a chivalrous way. Enemy’s still respected one another enough to respect the guidelines of combat. Fighting was done man to man, and both parties were ready and able. This changed with WWI. No longer was fighting seen as chivalrous. WWI was guerrilla warfare fueled by science. In 1914 the French deployed tear gas, wrecking mass havoc on their enemies. This was a far cry from the days of respectful combat. In 1915 the Germans introduced chlorine gas, a yellow gas that has the possibility to kill. In 1917 the Germans used Mustard Gas on their enemies. This resulted in 2,100 casualties the first time it was used and in the first three weeks, it was used the death of the previous year was matched. In 1918 the U.S. began to use mustard gas in artillery shells. In the 1930s Mussolini dropped mustard gas bombs on Ethiopia. 1945 was WWII, which was one of the darkest times that humanity has seen yet. Chemical warfare was at it's most utilized at this time, which of course reaped the most devastating results.
The discovery of the atom brought atomic theory to the forefront and proved that matter is composed of small particles. Then, scientists discovered the true composition and formation of this atom. Simultaneously, scientists were working with theories on radiation. These two categories combined yielded a darker fate: chemical warfare. With these discoveries, we can see the advent of modern chemistry and chemistry progression into the 19th and 20th century.
Works Cited
Encyclopedia Britannica: https://www.britannica.com/science/atom