Chem 110 Practice Midterm 2014

Transcription

1 Name Chem 110 Practice Midterm 2014 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the following statements is true? 1) A) Two electrons in the same orbital can have the same spin. B) It is possible for two electrons in the same atom to have identical values for all four quantum numbers. C) An orbital that penetrates into the region occupied by core electrons is more shielded from nuclear charge than an orbital that does not penetrate and therefore has a lower energy. D) An orbital that penetrates into the region occupied by core electrons is less shielded from nuclear charge than an orbital that does not penetrate and therefore has a lower energy. E) None of the above are true. 2) What is the maximum number of f orbitals that are possible in a given shell? 2) A) 1 B) 3 C) 7 D) 5 E) 9 3) In a px orbital, the subscript x denotes the. 3) A) size of the orbital B) probability of the shell C) axis along which the orbital is aligned D) energy of the electron E) spin of the electrons 4) Place the following in order of increasing radius. Br Na Rb A) Rb < Br < Na B) Br < Na < Rb C) Br < Rb < Na D) Rb < Na < Br E) Na < Rb < Br 4) 5) Which of the following quantum numbers describes the orientation of an orbital? 5) A) Schrödinger quantum number B) spin quantum number C) principal quantum number D) angular momentum quantum number E) magnetic quantum number 6) Determine the end (final) value of n in a hydrogen atom transition, if the electron starts in n = 2 and the atom absorbs a photon of light with a frequency of Hz. A) 3 B) 6 C) 7 D) 4 E) 1 6) 1

2 7) If an electron was in an orbital with 1 radial node and 3 angular nodes, what type of orbital is the electron occupying? A) 4f B) 5p C) 5f D) None of the above E) 4d 8) A green laser pointer has a wavelength of 532 nm. What is the energy of one mol of photons generated from this device? A) 225 kj/mol B) 3.74x10-17 kj/mol C) 2.25 kj/mol D) 3.74x10-19 kj/mol E) 784 kj/mol 7) 8) 9) Calculate the wavelength of a baseball (m = 155 g) moving at 32.5 m/s. 9) A) m B) m C) m D) m E) m 10) Choose the ground state electron configuration for Zn2. 10) A) [Ar]4s23d6 B) [Ar]4s23d8 C) [Ar]3d10 D) [Ar] E) [Ar]3d8 11) Which reaction below represents the second ionization of Sr? 11) A) Sr (g) + e Sr2 (g) B) Sr (g) Sr2 (g) + e C) Sr (g) + e Sr(g) D) Sr2 (g) + e Sr (g) E) Sr(g) Sr (g) + e 12) Which quantum numbers must be the same for the orbitals that they designate to be degenerate in a many-electron system? A) n, l, ml, and ms B) ms only C) n and l only D) n only E) n, l, and ml 12) 2

3 13) Calculate the energy of the violet light emitted by a hydrogen atom with a wavelength of nm. 13) A) J B) J C) J D) J E) J 14) How many orbitals are contained in the third principal level (n = 3) of a given atom? 14) A) 5 B) 9 C) 7 D) 18 E) 3 15) Why does an electron found in a 2s orbital have a lower energy than an electron found in a 2p orbital in multielectron systems? A) The larger number of electrons found in the 2p orbital leads to greater repulsion. B) There are more nodes found in the 2s orbital. C) Electrons in the 2s orbital are shielded by electrons in the 2p. D) Electrons in the 2s orbital can penetrate the 1s orbital and be closer to the nucleus. E) The shape of the orbital ultimately determines the energy of the electrons. 15) 16) According to the Heisenberg Uncertainty Principle: 16) A) an electron has a charge of C B) an electron can never appear in the exact same position twice C) you cannot accurately know both the position and momentum of an electron at the same time D) s orbitals are spherical in nature E) electrons must always absorb energy when moving to higher quantum levels 17) Which element is diamagnetic? 17) A) Zn B) Rb C) V D) F E) Li 18) Which of the following visible colors of light has the highest frequency? 18) A) orange B) yellow C) red D) blue E) green 19) What are the possible values for the orbital angular momentum quantum number l given the following values for the other three quantum numbers: n = 4, l =?, ml = 0, ms = +1/2 A) 0 B) 3 C) 0, 1, 2, or 3 D) None of the above E) 1, 2, 3, or 4 20) Determine the longest wavelength of light required to remove an electron from a sample of potassium metal, if the binding energy for an electron in K is kj/mol. A) 387 nm B) 885 nm C) 68.0 nm D) 113 nm E) 147 nm 19) 20) 21) Give the possible values for ml for a d orbital. 21) A) -2, -1, 0, 1, 2 B) 0, 1, 2 C) 1, 2, 3 D) -1, 0, 1 3

4 22) Which of the following represents the orbit with the largest radius? 22) A) n=2 orbit for Be3+ B) n=3 orbit for Li2+ C) n=1 orbit for H D) n=3 orbit for H E) n=4 orbit for He+ 23) How many nodes are found in a 3s orbital? 23) A) 0 B) 1 C) 2 D) 3 E) 4 24) Calculate the energy change associated with the transition from n = 4 to n = 1 in the hydrogen atom. 24) A) J B) J C) J D) J E) J 25) It is possible to determine the ionization energy for hydrogen using the Bohr equation. Calculate the ionization energy for an atom of hydrogen, making the assumption that ionization is the transition from n = 1 to n =. A) J B) J C) J D) J E) J 25) 26) An electron cannot have the quantum numbers n =, l =, ml =. 26) A) 2, 0, 0 B) 1, 1, 1 C) 3, 1, -1 D) 3, 2, 1 E) 2, 1, -1 27) Give the complete electronic configuration for Mn. 27) A) 1s22s22p63s23p64s24p5 B) 1s22s22p63s23p64s13d6 C) 1s22s22p63s23p64s24d5 D) 1s22s22p63s23p64s23d5 28) Determine the energy change associated with the transition from n = 3 to n = 2 in the hydrogen atom. A) J B) J C) J D) J E) J 28) 4

5 29) Which of the following statements is true? 29) A) Since electrons have mass, we must always consider them to have particle properties and never wavelike properties. B) All orbitals in a given atom are roughly the same size. C) Atoms are roughly spherical because when all of the different shaped orbitals are overlapped, they take on a spherical shape. D) We can sometimes know the exact location and speed of an electron at the same time. E) All of the above are true. 30) Calculate the wavelength (in nm) of the blue light emitted by a mercury lamp with a frequency of Hz. A) 436 nm B) 206 nm C) 485 nm D) 675 nm E) 229 nm 30) 5

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