Spectroscopy - Based on his model, Bohr was able to derive...

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Based on his model, Bohr was able to derive a mathematical expression for the energy of each orbit available for the hydrogen atom, E n = –2.178 x 10 –18 J Z 2 n 2 in which n is an integer representing the size and energy of each orbit, called the principal quantum number , Z is the charge on the nucleus of the atom (+1 for hydrogen, +2 for helium, +3 for lithium, etc.), and 2.178 x 10 –18 J is a constant called the Rydberg’s constant . The value of the principal quantum number, n , could range from 1 to infinity ( ), the larger the value of n , the larger the size and energy of the orbit (Figure 3.25). The orbit with the smallest size and the lowest energy, n = 1, is the orbit closest to the nucleus. The electron in a hydrogen atom is normally in this orbit and is in its ground state. Since the negatively charged electron is attracted to the positively charged nucleus, the electron must absorb energy to move further from the nucleus and to go from a lower orbit with a lower energy (smaller n value) to a higher orbit with a higher energy (larger n value). When the electron is at a higher energy orbit, it is in an excited state. Conversely, energy is emitted for the reverse process, when an electron moves from a higher orbit with higher energy to a lower orbit with lower energy. The negative sign in the
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Spectroscopy - Based on his model, Bohr was able to derive...

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