![]() Light is emitted by an atom when an electron jumps from one of itsĪllowed orbits to another. Each orbit represents a definite energy for the electronsĢ. Electrons can only occupy certain orbits or shells in an atom. ![]() The experimental evidence known at the time, particularly the evidence providedīohr's theory may be summarized in the following two statements:ġ. Rutherford had just produced experimental evidence that the atom has a veryīy electrons, so Bohr now took over the theoretical problems of Rutherford'sĪtom in an effort to put forward an atomic model that would agree with One of the leading atomic physicists in the world, was professor of physics. Within a few months Bohr moved to Manchester where Ernest Rutherford, Sphere of positively charged electricity, with negatively charged electrons moving about inside the sphere in such numbers that the atom was electrically At this time, the main group of physicists at Cambridge, inĬommon with many physicists in the world, thought the atom to be like a Thomson in the Cavendish Laboratory at Cambridge. In 1903 Bohr entered Copenhagen University, andĮight years later left with a doctorate degree and a keen interest in theĪrriving in England in the autumn of 1911, Bohr began work under J. His father was professor of physiologyĪt Copenhagen University. Niels Henrik David Bohr was born in 1885. Used, with modifications, to describe the atom today. Of hydrogen that Bohr put forward his model of the atom, which is still Is excited in a gas discharge tube it emits its well-known line spectrum. These line or band spectra willĪlways be the same for gas atoms or molecules of a given element, and provideĪ valuable method of identification for elements. The spectra of gasesĪnd vapors, however, are in the form of discrete lines or bands. With bands of different colors merging into each other. The spectrum of light emitted by incandescent solids is continuous, The light of different colors of which it is composed. If light is passed through a prism or diffraction Vapors are heated, or if their atoms or molecules are excited in an electricalĭischarge, but there is an important difference in the light produced in When a solid material is heated it becomes incandescent, that is, it emits light. Modern theories usually use orbitals to describe the behavior Uncertainty principle, since it postulates definite paths and momentaįor electrons as they move around the nucleus. The electron orbits the nucleus at a definite distance. Bohr's model and postulates do not explain this phenomenon.The Bohr atom is a model of the atom, firstĭescribed by Niels Bohr, that explains the emission and absorption of radiation as transitions between stationary electronic states in which Spectral lines undergo splitting when a sample of gas is affected by an electric field (Stark effect) and magnetic field (Zeeman effect).These are referred to as hyperfine spectral lines. Bohr's model does not explain the presence of hyperfine lines. Each spectral line, when examined at higher magnification, actually consists of a number of smaller fine lines.The accuracy decreases as the effective nuclear charge of an atom or ion increases (due to greater number of protons). Predictions made by Bohr’s model is only accurate for the hydrogen atom. ![]()
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