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The Electron: A Major Player in Chemistry
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Did you know that 1997 is the centennial of the discovery of the electron? The electron was discovered on April 30, 1897 by British Physicist Joseph John Thomson of Cambridge University, U.K.. Although Dr. Thomson wasn’t a chemist, the discovery is very important to the understanding of chemistry. The discovery of the electron led to the Bohr Model of the atom, the quantum theory of atomic structure, and the fundamental understanding of the periodic table and chemical bonding.
The Bohr model of the atom was proposed in 1913 by Niels Bohr. The model is a theory for the electronic structure of the hydrogen atom. According to this theory, the hydrogen atom contains a nucleus consisting of one proton and an electron which exists only in circular orbitals concentrically arranged around the nucleus. Each orbital (energy level) has an energy associated with it and no two orbitals are the same. When the electron is in the inner most energy level it is said to be in the ground state; however, when the electron is promoted to one of the other energy levels it is said to be in an excited state. The quantum theory was proposed in 1900 by Max Planck. The theory states that radiant energy could be absorbed or given off in discrete quantities called quanta. The energy of the quantum, E, is proportional to the frequency of the radiation, n, and a proportionality constant, h, called the Planck’s constant. This is better known as the equation, E = hn.
Thus, it is logical to assume that without these theories chemistry would not be as advanced as it is today. Indeed, chemical reactions, on a first approximation, may be visualized as involving the reorganization of electrons. The discovery of the electron is very important to society as it has facilitated the invention of such things as electricity, the computer, the electron microscope, television, radio, the microwave, the periodic table, digital phone, lasers, and magnetic recording. In other words, the electron is ubiquitous in everyday life.
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