2/29/2024 0 Comments Nitrogen atomic emission spectrumBecause a hydrogen atom with its one electron in this orbit has the lowest possible energy, this is the ground state The most stable arrangement of electrons for an element or a compound., the most stable arrangement for a hydrogen atom. Thus the orbit with n = 1 is the lowest in energy. ![]() The latter condition is arbitrarily assigned an energy of zero. The negative sign in Equation 6.9 is a convention indicating that the electron-nucleus pair has a lower energy when they are near each other than when they are infinitely far apart, corresponding to n = ∞. Where ℛ is the Rydberg constant, h is Planck’s constant, c is the speed of light, and n is a positive integer corresponding to the number assigned to the orbit, with n = 1 corresponding to the orbit closest to the nucleus. In 1885, a Swiss mathematics teacher, Johann Balmer (1825–1898), showed that the frequencies of the lines observed in the visible region of the spectrum of hydrogen fit a simple equation that can be expressed as follows: If a hydrogen atom could have any value of energy, then a continuous spectrum would have been observed, similar to blackbody radiation. Thus the energy levels of a hydrogen atom had to be quantized in other words, only states that had certain values of energy were possible, or allowed. Part of the explanation is provided by Planck’s equation ( Equation 6.5): the observation of only a few values of λ (or ν) in the line spectrum meant that only a few values of E were possible. Such emission spectra were observed for many other elements in the late 19th century, which presented a major challenge because classical physics was unable to explain them. (b) When the light emitted by a sample of excited hydrogen atoms is split into its component wavelengths by a prism, four characteristic violet, blue, green, and red emission lines can be observed, the most intense of which is at 656 nm. (a) A sample of excited hydrogen atoms emits a characteristic red light. With sodium, however, we observe a yellow color because the most intense lines in its spectrum are in the yellow portion of the spectrum, at about 589 nm.įigure 6.9 The Emission of Light by Hydrogen Atoms The light emitted by hydrogen atoms is red because, of its four characteristic lines, the most intense line in its spectrum is in the red portion of the visible spectrum, at 656 nm. When the emitted light is passed through a prism, only a few narrow lines, called a line spectrum A spectrum in which light of only a certain wavelength is emitted or absorbed, rather than a continuous range of wavelengths., are seen ( Figure 6.9 "The Emission of Light by Hydrogen Atoms"), rather than a continuous range of colors. Unlike blackbody radiation, the color of the light emitted by the hydrogen atoms does not depend greatly on the temperature of the gas in the tube. For example, when a high-voltage electrical discharge is passed through a sample of hydrogen gas at low pressure, the resulting individual isolated hydrogen atoms caused by the dissociation of H 2 emit a red light. ![]() zip file containing this book to use offline, simply click here.Īlthough objects at high temperature emit a continuous spectrum of electromagnetic radiation ( Figure 6.6 "Relationship between the Temperature of an Object and the Spectrum of Blackbody Radiation It Emits"), a different kind of spectrum is observed when pure samples of individual elements are heated. You can browse or download additional books there. More information is available on this project's attribution page.įor more information on the source of this book, or why it is available for free, please see the project's home page. Additionally, per the publisher's request, their name has been removed in some passages. However, the publisher has asked for the customary Creative Commons attribution to the original publisher, authors, title, and book URI to be removed. Normally, the author and publisher would be credited here. This content was accessible as of December 29, 2012, and it was downloaded then by Andy Schmitz in an effort to preserve the availability of this book. See the license for more details, but that basically means you can share this book as long as you credit the author (but see below), don't make money from it, and do make it available to everyone else under the same terms. This book is licensed under a Creative Commons by-nc-sa 3.0 license.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |