mportant during the last part of the nineteenth century. William Oswald and Jacobus Van't Hoff did work on chemical equilibriums while Svante August formulated a theory of ionization. Accurate atomic weights were determined by Theodore Richards and helium and other inert gasses were discovered by Rayleigh and Ramsay. After 1900, Francis Aston developed a machine to demonstrate the existence of isotopes, the mass spectrometer. Harold Urey isolated an isotope of hydrogen which has become a very important chemical tracer in modern chemistry. By the twentieth century nuclear chemistry and physics were starting to evolve. In 1934, Joliot- Curies discovered that all elements could be made radioactive. By the 1940's nuclear reactions had been performed with all elements from one to ninety-eight. In the first twenty-five years of the century, the interpretation of the structure of atoms was of important research. In the 1920's and 30's the nature of chemical reactions and the relationship between atoms and molecules was comprehendible. One of chemistry's most important advancements was in the development of new materials such as plastics. This new knowledge led to the production of materials with particular properties such as synthetic fibers and synthetic rubber. Some notable achievements in chemistry that people often use, but don't appreciate the chemistry behind it are asprin, penicillin, and many other drugs used to fight diseases. In the past sixty years the pharmaceutical industry has grown tremendously due to advancements in chemistry. Another example is the ability to analyze and synthesize DNA and RNA. Biochemists have also been able to produce hormones through genetic engineering. If it weren't for chemistry, many diseases would have had a chance to infect large amounts of population and people might not be as healthy as they are in modern times. It's hard for people to realize how much activity chemistry has in their daily lives. ...
