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Articles: My Thoughts | In quest of Infinity-06
- Prof. venkata ramanamurty mallajosyula
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Where structure was concerned, Bohr said that the atom was like a mini solar system with a tiny atomic nucleus at the centre [rather like our Sun] and electrons going round it in circular orbits. In the Bohr model, all the positive charge of the atom was locked up in a tiny region called the atomic nucleus or just nucleus for short. The electrons that carried the negative charge whirled around the nucleus like the planets. Clearly, Bohr was mimicking the solar system and there was nothing wrong in that. Scientists often make models, based on examples presented by Nature itself.
British Scientist J.J. Thomson of Cambridge Physicist Niels Bohr of Denmark
After imagining all this, Bohr then wanted to describe the motion of the electrons, calculate their energies and so forth. For doing this, one needed a theory of mechanics and all that one had then was Newton’s theory for describing the behaviour of moving bodies, [modified by Einstein to include relativity, if the objects moved real fast, that is to say at speeds close to that of light].
The very first useful and working model of the atom was due to Neils Bohr. In the Bohr model, the atom is like a mini solar system, with the atomic nucleus in the centre and the electrons going round the nucleus in circular orbit. In the simplest atom, namely hydrogen, the nucleus is just a single proton and there is thus only one electron going round the nucleus. [The number of electrons is always the same as the number of protons – that is the way Nature maintains electrical balance!] Normally, the electron moves in the lowest orbit but it if the electron is given some energy [physicists say excitation], then the electron moves into an outer orbit. Obviously, it has plenty of them to choose from.
The farther the orbit, the greater is the energy of the electron in the excited state. Atoms do not like to be in an excited state; so what they do is to get rid of the excess energy by emitting radiation, which then allows the electron to settle down into its lowest state, rightfully called the ground state. Thus, radiation emitted by atoms and the energy levels available to the atom are intimately connected. This is a great boon to physicists who can, by studying the spectrum of the emitted radiation, literally finger print the atom – this is rather like DNA finger printing, so common these days.
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