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

Transcription

1 Take Home Exam Chem 1A Fall Chapters 6 to 9: You may us any resource you wish accept people. On your honor, you may not ask another person for help. Show your work on every answer. Partial credit will be given. Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The energy of a photon that has a frequency of s-1 is J. 1) A) B) C) D) E) ) The n = 2 to n = 6 transition in the Bohr hydrogen atom corresponds to the of a photon 2) with a wavelength of nm. A) emission, 389 B) absorption, 411 C) absorption, 657 D) emission, 93.8 E) emission, 411 3) The principal quantum number for the outermost electrons in a Br atom in the ground state is 3). A) 5 B) 2 C) 3 D) 4 E) 1 4) An electron cannot have the quantum numbers n =, l =, ml =. 4) A) 1, 1, 1 B) 3, 2, 1 C) 2, 0, 0 D) 2, 1, -1 E) 3, 1, -1 5) In which orbital does an electron in a phosphorus atom experience the greatest effective nuclear 5) charge? A) 1s B) 2s C) 2p D) 3s E) 3p 6) Which one of the following configurations depicts an excited oxygen atom? 6) A) 1s22s22p23s2 B) 1s22s22p1 C) 1s22s22p2 D) 1s22s22p4 E) [He]2s22p4 1

2 7) The complete electron configuration of gallium, element 31, is. 7) A) 1s22s22p63s23p63d104s24p1 B) 1s42s42p83s43p84s3 C) 1s22s22p103s23p104s23d3 D) 1s42s42p63s43p64s43d3 E) 1s42s42p103s43p9 8) In general, as you go across a period in the periodic table from left to right: 8) (1) the atomic radius ; (2) the electron affinity becomes negative; and (3) the first ionization energy. A) increases, increasingly, decreases B) increases, increasingly, increases C) decreases, increasingly, decreases D) decreases, increasingly, increases E) decreases, decreasingly, increases 9) Element M reacts with chlorine to form a compound with the formula MCl2. Element M is more 9) reactive than magnesium and has a smaller radius than barium. This element is. A) K B) Be C) Ra D) Na E) Sr 10) The atomic radius of main-group elements generally increases down a group because. 10) A) the principal quantum number of the valence orbitals increases B) effective nuclear charge decreases down a group C) effective nuclear charge increases down a group D) effective nuclear charge zigzags down a group E) both effective nuclear charge increases down a group and the principal quantum number of the valence orbitals increases 11) The formal charge on nitrogen in NO3 - is. 11) A) +1 B) +2 C) -2 D) 0 E) -1 2

3 12) The chloride of which of the following metals should have the greatest lattice energy? 12) A) potassium B) cesium C) sodium D) lithium E) rubidium 13) The central atom in violates the octet rule. 13) A) SeF2 B) AsF3 C) NH3 D) CF4 E) BF3 14) The molecular geometry of is square planar. 14) A) XeF2 B) CCl4 C) ICl3 D) XeF4 E) PH3 15) The molecular geometry of the SF2 molecule is. 15) A) bent B) linear C) trigonal planar D) tetrahedral E) octahedral 16) The hybridization of the central atom in the XeF4 molecule is. 16) A) sp3 B) sp3d2 C) sp2 D) sp3d E) sp 17) According to VSEPR theory, if there are three electron domains in the valence shell of an atom, 17) they will be arranged in a(n) geometry. A) octahedral B) linear C) trigonal planar D) trigonal bipyramidal E) tetrahedral 3

4 18) The hybridization of the oxygen atom labeled y in the structure below is.the C-O-H 18) bond angle is. A) sp3d2, 90 B) sp2, C) sp, 90 D) sp, 180 E) sp3, ) The Lewis structure of carbon dioxide is given below. The hybridization of the carbon atom in 19) carbon dioxide is. A) sp3 B) sp C) sp2 D) sp2d2 E) sp2d 20) A valid Lewis structure of cannot be drawn without violating the octet rule. 20) A) NF3 B) SiF4 C) SeF4 D) PO4 3- E) CF4 21) According to MO theory, overlap of two s atomic orbitals produces. 21) A) two bonding molecular orbitals B) one bonding molecular orbital and one hybrid orbital C) one bonding molecular orbital and one antibonding molecular orbital D) two bonding molecular orbitals and one antibonding molecular orbital E) two bonding molecular orbitals and two antibonding molecular orbitals 4

5 22) Of the following, appear(s) to gain mass in a magnetic field; proof of the presence of 22) unpair electrons. B2 N2 O2 A) O2 only B) N2 and O2 C) N2 only D) B2 and O2 E) B2 and N2 SHORT ANSWER. Write the word, phrase, or numerical value that best completes each statement or answers the question. 23) When electrons are removed from a lithium atom they are removed first from which 23) orbital? 24) An added electron to the element bromine goes into which orbital? 24) 25) Electrons in bonds remain localized between two atoms. Electrons in 25) bonds can become delocalized between more than two atoms. ESSAY. Write your answer in the space provided. Show all your work. 26) Determin the lattice enthalpy of Potasium Iodide. Show all you work using balanced equations. 5

6 27) Of the hydrogen halides, only is a weak acid. Describe each acid and tell me why you think the acidity varies the way it does in as much detail as possible. 28) Draw the molecular orbital diagram for N-N and O-O. Which molecule would be more stable if it gained one electron? Explain 6

7 29) Describe what makes Hydrogen unique among all the elements. 30) Draw the different types of resonance structures that can be drawn for the ion SO3 2-. Circle all structure that have all the atoms which satisfy the octet rule. Do these on scratch and then make them look nice on this paper! 31) Draw the Lewis structure of N2H2. Describe the geometry and hybridization of each nitrogen atom. 7

8 32) Describe the purpose of resonance strucutres. Give an example which illustrates this idea. 33) Describe the purpose of the hybridization theory. Give an example which illustrates this idea. 34) Perfluorate is not stable but perchlorate, perbromate, and periodate do exist. Explain why you think this might be. 8