The Bohr’s Atomic Model
In 1913, a Danish physicist named Niels Bohr put Rutherford's findings together with the observed spectra to come up with a new model of the atom in a real leap of intuition. I believe that the Bohr’s model of atom explains well about the atomic theory, because in his experiments it is shown and explained the structure of an atom. His famous suggestion is about that the electrons orbit around the nucleus of an atom. Bohr experimented with atomic spectrum that proved his suggestion. The Bohr’s experiments with atomic spectra explained how each element had a unique spectrum and the wavelength of each line within a spectrum had a specific energy. When atoms in the gas tubes absorbed the energy from the electric current, the electrons became excited and jumped from low energy levels (close to the nucleus) to high energy levels (farther out from the nucleus). The excited electrons would fall back to their original levels and emit energy as light. Because there were specific differences between the energy levels, only specific wavelengths of light were seen in the spectrum. Bohr’s Periodic behavior of elements described how did elements with similar properties had similar atomic spectra. Bohr also explained that Each electron orbit of the same size or energy (shell) could only hold so many electrons. For example, the first shell could hold two electrons, the second could hold eight electrons, the third could hold 18 electrons, the fourth 32 and so on until reaching the seventh. When one shell was filled, electrons were found at higher levels. Chemical properties were based on the number of electrons in the outermost shell. Elements with full outer shells do not react. Other elements take or give up electrons to get a full outer shell.
As it turns out, Bohr's model is also useful for explaining the behavior of lasers, although these devices were not invented until the middle of the 20th century....
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