* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 29: Atomic Physics
Survey
Document related concepts
Quantum electrodynamics wikipedia , lookup
Particle in a box wikipedia , lookup
Ferromagnetism wikipedia , lookup
Wave–particle duality wikipedia , lookup
Bremsstrahlung wikipedia , lookup
Auger electron spectroscopy wikipedia , lookup
Hydrogen atom wikipedia , lookup
Rutherford backscattering spectrometry wikipedia , lookup
Tight binding wikipedia , lookup
Atomic orbital wikipedia , lookup
X-ray photoelectron spectroscopy wikipedia , lookup
Atomic theory wikipedia , lookup
Theoretical and experimental justification for the Schrödinger equation wikipedia , lookup
Transcript
Chapter 29: Atomic Physics 1. How many possible subshells are there for the n = 4 level of hydrogen? (a) 5 (b) 4 (c) 3 (d) 2 (e) 1 Answer: (b). The number of subshells is the same as the number of allowed values of ℓ. The allowed values of ℓ for n = 4 are ℓ = 0, 1, 2, and 3, so there are four subshells. 2. When the principal quantum number is n = 5, how many different values of (a) ℓ and (b) mℓ are possible? Answer: (a) Five values (0, 1, 2, 3, 4) of ℓ and (b) nine different values (−4, −3, −2, −1, 0, 1, 2, 3, 4) of mℓ as follows: ℓ 0 1 2 3 4 mℓ 0 −1, 0, 1 −2, −1, 0, 1, 2 −3, −2, −1, 0, 1, 2, 3 −4, −3, −2, −1, 0, 1, 2, 3, 4 3. Sketch a vector model (shown in Fig. 29.7 for ℓ = 2) for ℓ = 1. Figure 29.7 A vector model for ℓ = 2. (a) The allowed projections of the orbital angular momentum L relative to a magnetic field that defines the z direction. (b) The orbital angular momentum vector L lies on the surface of a cone. Answer: The vector model for ℓ = 1 is shown below. 4. Rank the energy necessary to remove the outermost electron from the following three elements, smallest to largest: lithium, potassium, cesium. Answer: Cesium, potassium, lithium. The higher the value of Z, the closer to zero is the energy associated with the outermost electron and the smaller is the ionization energy. 5. What are the initial and final shells for an Mβ line in an x-ray spectrum? Answer: Final: M. Initial: O (because the subscript β indicates that the initial shell is the second shell higher than M). 6. In an x-ray tube, as you increase the energy of the electrons striking the metal target, (i) the wavelengths of the characteristic x-rays (a) increase, (b) decrease, or (c) do not change and (ii), the minimum wavelength of the bremsstrahlung (a) increases, (b) decreases, or (c) does not change. Answer: (i), (c). The wavelengths of the characteristic x-rays are determined by the separation between energy levels in the atoms of the target, which is unrelated to the energy with which electrons are fired at the target. The only dependence is that the incoming electrons must have enough energy to eject an atomic electron from an inner shell. (ii), (b). The minimum wavelength of the bremsstrahlung is associated with the highest-energy photon. This photon comes from an electron striking the target and giving up all its energy to electromagnetic radiation in one collision. Therefore, higher-energy incoming electrons will result in higher-energy photons with shorter wavelengths.