MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Transcription

1 Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Situation 41.1 An atom has completely filled inner shells and a single valence electron in an excited p state. The filled inner shells have an orbital momentum equal to zero. 1) In Situation 41.1, the magnitude of the orbital angular momentum of the atom is closest to: A) 1.4ħ 1 B) 1.2ħ 1 C) 1.0ħ 1 D) 2.0ħ 1 E) 1.7ħ 1 1) 2) In Situation 41.1, a magnetic field is applied. The set of possible angles between the magnetic field and the orbital angular momentum is: A) 45, 90 B) 90 C) 45, 90, 135 D) 45, 135 E) 45 2) 3) The total number of electron states (including spin states), for which l = 1 in the K, L, and M shells is equal to: A) 12 B) 6 C) 10 D) 16 E) 8 3) 4) The only valid electron state and shell designation among the following is: A) 2p, L B) 1s, L C) 2s, K D) 1p, K E) 3f, M 4) 5) The only invalid electron state and shell designation among the following is: A) 2s, L B) 3d, M C) 3s, M D) 1s, K E) 2d, L 5) 6) The correct ground state electron configuration of boron (Z = 5) is: A) 1s 2 2p 3 B) 1s 2 2s 2 2p C) 1s 2 2s 2 2p 3 D) 1s 2 2p 2 3s E) 1s 2 1p 2 2s 7) The only valid ground state electron configuration among the following is: A) 1s 2 2s 2 2p 3 B) 1s 2 2s 2 2p 5 C) 1s 2 2s 2 2p 6 3s 2 3p D) 1s 2 2s 2 2p 6 3s E) 1s 2 2s 2 2p 4 3s 2 6) 7) 1

2 8) The normalized wave function for a hydrogen atom in the 1s state is given by: 8)!(r) = 1/ π! 3 0 exp(-r/! o) where!o is the Bohr radius. The probability of finding the electron at a distance greater than 7.8!o from the proton is closest to: A) B) C) D) E) ) An s state (l = 0) energy level is split into two levels by an applied magnetic field. A photon of 38-GHz microwave radiation induces a transition between the two levels. The applied magnetic field is closest to: A) 0.22 T B) 0.79 T C) 1.4 T D) 8.5 T E) 1.8 T 9) 10) An alkali metal atom is in the ground state. The orbital angular momentum equals zero and the spin angular momentum is entirely due to the single valence electron. A magnetic field is applied that splits the ground state energy level into two levels, 21 µev apart. The applied magnetic field, in SI units, is closest to: A) 0.14 B) 0.31 C) 0.22 D) 0.18 E) ) 11) An alkali metal atom is in the ground state. The orbital angular momentum equals zero and the spin angular momentum is entirely due to the single valence electron. A magnetic field is applied that splits the ground state energy level into two levels, 99 µev apart. A photon, absorbed by the atom, induces a transition between the two levels. The wavelength of the photon is closest to: A) 13 mm B) 17 mm C) 27 mm D) 25 mm E) 21 mm 11) 12) An atom in a state with l = 1 decays to its ground state (with l = 0). A photon of wavelength 570 nm is emitted in the process. When the same process takes place in the presence of an intense magnetic field a change in the spectrum is observed. With the magnetic field present, one of the emitted lines observed has a wavelength of nm. Which of the following wavelengths would you expect to be present also? A) nm B) nm C) nm D) nm E) nm 12) 2

3 13) Perhaps the most famous observation in spectroscopy was the recognition that the yellow-orange line in the spectrum of sodium is in fact a narrowly separated doublet. The explanation of this splitting is most closely related to A) the existence of spin angular momentum of the electron. B) the existence of quantized orbital angular momentum of the electron. C) the de Broglie wavelength of the electron. D) the exclusion principle. E) solution of the Schrodinger equation. 13) 14) Consider an atom with the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6. Which of the following is an accurate statement concerning this atom? A) This atom is in an excited state. B) The atomic number of this atom is Z = 11. C) This atom has a nonzero angular momentum. D) This atom would probably be very inert chemically. E) This atom is most likely to give rise to an ion with charge +2e. 14) 15) A potassium atom (Z = 19) in the ground state has filled K, L, and M shells and a 4s electron. The inner shells have zero total angular momentum. A magnetic field of 4.3 T is applied. The magnitude of the total angular momentum of the atom is closest to: A) zero B) 0.5 h C) 0.7 h D) 1.0 h E) 0.9 h 15) 16) A potassium atom (Z = 19) in the ground state has filled K, L, and M shells and a 4s electron. The inner shells have zero total angular momentum. A magnetic field of 0.5 T is applied. The angle between the total angular momentum and the axis of the magnetic field is closest to: A) 50 B) 40 C) 60 D) 45 E) 55 16) 17) A potassium atom (Z = 19) in the ground state has filled K, L, and M shells and a 4s electron. The inner shells have zero total angular momentum. A magnetic field of 0.7 T is applied. The ground energy of a potassium atom is ev. This energy level is split by the applied magnetic field into two levels. The difference in energy of these two levels is closest to: A) 95 µev B) 67 µev C) 39 µev D) 81 µev E) 53 µev 17) 18) The ground state for the single valence electron of a gold atom (Z = 79) is 6s and its energy is ev. The effective nuclear charge for this 6s electron is closest to: A) 3.5 B) 4.0 C) 4.5 D) 3.0 E) ) 19) The ground state for the single valence electron of a rubidium atom (Z = 37) is 5s and its energy is ev. The valence electron is excited into the 5g state. Assume this 5g electron is entirely outside the electron cloud of the 36 other electrons in the atom. The energy of the 5g electron is closest to: A) ev B) ev C) ev D) ev E) ev 19) 3

4 Situation 41.2 A barium atom (Z = 56) has two outer electrons in the 6s state when the atom is on the ground configuration. A singly charged Ba+ ion is formed when one of the 6s electrons is removed. The energy required to remove this electron is 5.21 ev. 20) In Situation 41.2, the energy required to remove the remaining 6s electron is ev. The effective nuclear charge for the remaining 6s electron of a Ba + ion is closest to: A) 4.1 B) 4.4 C) 5.1 D) 4.8 E) ) 21) In Situation 41.2, the single outer electron of a Ba + ion is excited into the 6h state (l = 5). Assume this 6h electron is entirely outside the electron cloud of the 54 electrons in the inner shells. The energy of this 6h electron is closest to: A) -1.9 ev B) -0.4 ev C) -1.1 ev D) -1.5 ev E) -0.7 ev 21) 22) An electron in an atom makes a transition between the M and K shells, and in the process emits a photon of wavelength m. (Note: h = ev s, c = m/s.) The effective atomic number of the nucleus of this atom is closest to: A) 1190 B) 97.6 C) 104 D) 34.5 E) ) Situation 41.3 The magnitude of the orbital angular momentum of an electron in a certain atom is equal to ħ.. 23) In Situation 41.3, the orbital angular momentum quantum number of the electron is closest to: A) 1 B) 4 C) 2 D) 5 E) 3 23) 24) In Situation 41.3, which of the following numbers could be the principal quantum number of the electron? A) 4 B) 0 C) 1 D) 2 E) 3 24) 25) In Situation 41.3, which of the following angles could NOT be the angle between the orbital angular momentum vector of the electron and an arbitrary z-direction? A) 54.7 B) 73.2 C) 90.0 D) 0.00 E) ) 26) The target of an x-ray tube is a metallic element. The smallest wavelength produced in the continuous x-ray spectrum is 250 pm. The K! line of the characteristic x-ray spectrum is barely observed at the same wavelength of 250 pm. The atomic number of the element of the target, is: A) 21 B) 22 C) 19 D) 20 E) 23 26) SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 27) Consider the n = 2 shell. (a) What is the largest value of the angular momentum quantum number, l, in this shell? (b) How many electrons can be placed in this shell? 27) 28) The energy of an electron in the p-level of an atom is changed in the presence of a magnetic field of magnitude 4.6 T. What is the difference between the largest and 28) smallest possible energies? Recall that the Bohr magneton is J/T. 4

5 29) Consider a hydrogen atom in the n = 1 state in a magnetic field. For what value of the magnetic field is the splitting between the s = +1 and s = -1 levels equal to ev? (Note: h = J s, e = C, and m = kg.) 29) 30) An atom with atomic number 9 is in its ground state. How many electrons are in its outermost shell? 30) 31) The ionization energy of the outermost electron in Li is ev. What is the effective charge seen by this outermost electron? (Li has 2 energy levels.) 31) 32) The x-ray spectrum for an atom shows a strong K! line with a wavelength of nm. How many protons does the nucleus of this atom contain? 32) 5

6 Answer Key Testname: UNTITLED1 1) A 2) C 3) A 4) A 5) E 6) B 7) E 8) E 9) C 10) D 11) A 12) E 13) A 14) D 15) E 16) E 17) E 18) E 19) C 20) C 21) D 22) D 23) E 24) A 25) D 26) E 27) (a) 1 (b) 8 28) J 29) 0.24 T 30) 7 31) 1.26 e 32) 17 6