Notable Dates in Chemistry History
By Naga Nandini
Once upon a time, humans respired without knowledge of oxygen and the chemical properties of gases, benzene defied molecular description and broken bones healed without the mending benefits of x-ray technology. While most of the well-known breakthroughs in chemistry resulted from years of hard work, many were happy, observational accidents. Here are some of the notable discoveries made in recent centuries and the scientists who made them.
1864: Julius Meyer, a German chemist and competitor of Dmitri Mendeleev, prepared a table of 28 elements grouped into six families, using atomic weight and valence for classification purposes. Meyer understood that an atom’s affinity for bond forming could be used to classify and predict the behavior of elements yet-to-be discovered.
1898: Isolation of polonium and radium. Marie and Pierre Curie discovered these highly reactive substances derived from uranium ore. They shared the Nobel Prize in Physics with Henri Becquerel for their joint discovery of the radioactivity.
1913: Introduction of the Bohr model of the hydrogen atom. The Danish physicist, Niels Bohr, demonstrated that electrons travel around a positively charged nucleus in circular orbits, with electrostatic forces causing attraction.
1932: Discovery of the neutron. James Chadwick identified this uncharged particle in isotopes, which accounts for why atoms with the same atomic number can vary greatly in mass.
1938: Nuclear fission achieved. The process of fission in uranium and thorium was discovered by Otto Hahn, the Father of Nuclear Chemistry. Hahn and his associates worked on uranium fission reactions and listed about 25 elements with 100 isotopes. He was awarded the Nobel Prize for his outstanding work in fission of heavy atomic nuclei.
1953: Double helix structure proposed. James Watson and Francis Crick discovered the ladder-like structure of DNA and proffered a new understanding of heredity using some data gathered by Rosalind Franklin. They shared the Nobel Prize in Medicine with Maurice Wilkins in 1962 for this great leap forward.
In the past century, the very existence of the atom was questioned. Today, it is possible to maneuver atoms using a scanning, tunneling microscope. Chemistry has come a long way in a relatively short period of time; it plays a prominent role today in genetics, biotechnology and nanotechnology.
- What are some other fields that chemistry plays an important role in today?
- What are the most important discoveries and breakthroughs in chemistry in the past two decades?