practice_exam_3_and_answer_key - CHM-201-03 PRACTICE EXAM...

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Unformatted text preview: CHM-201-03 PRACTICE EXAM III (Chapters 7-10) December 2009 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. (2 points each) 1) The energy of a photon of light is __________ proportional to its frequency and __________ proportional to its wavelength. A) directly, inversely B) directly, directly C) indirectly, not D) inversely, inversely E) inversely, directly 2) What color of visible light has the longest wavelength __________ ? A) violet B) green C) yellow D) red E) blue 3) The bond angles in CO32– are expected to be A) a little less than 109.5°. B) 109.5°. D) 120°. E) a little more than 120°. 4) The __________ subshell contains only one orbital. A) 6f B) 4s C) 1p D) 3d C) a little less than 120°. E) 5d E) [Ar]3s23d10 5) The ground state electron configuration for Zn is __________. A) [Ar]4s23d10 B) [Kr]3s23d10 C) [Kr]4s23d10 D) [Ar]4s13d10 6) All of the __________ have a valence shell electron configuration ns1. A) noble gases B) alkali metals C) chalcogens D) halogens E) alkaline earth metals 7) Elements in the modern version of the periodic table are arranged in order of increasing__________. A) oxidation number B) average atomic mass C) number of isotopes D) atomic mass E) atomic number 8) In general, as you go across a period in the periodic table from left to right: (1) the atomic radius __________; and the first ionization energy __________. A) decreases, increases B) decreases, decreases C) increases, decreases D) decreases, increases E) increases, increases 9) The __________ have the lowest ionization energy. A) alkali metals B) chalcogens C) transition metals D) halogens E) alkaline earth metals 10) In the Lewis symbol for a fluorine atom, there are __________ paired and __________ unpaired electrons. A) 4,1 B) 6, 1 C) 4, 2 D) 0, 5 E) 2, 5 11) Based on the octet rule, phosphorus most likely forms a __________ ion. B) P ¡ ¡ A) P3 C) P 5 D) P5 E) P3 12) The only noble gas without eight valence electrons is __________. A) Ne B) Ar C) He D) Kr E) All noble gases have eight valence electrons. 13) Which of the following would have to lose two electrons in order to achieve a noble gas electron 1 configuration __________? O Sr Na Se Br A) Na B) Sr, O, Se C) Sr D) O, Se E) Br 14) A double bond consists of __________ pairs of electrons shared between two atoms. A) 1 B) 2 C) 3 D) 4 E) 6 15) A polar bond will form between two __________ atoms of __________ electronegativity. A) different, opposite B) identical, different C) similar, different D) identical, equal E) different, different 16) The formal charge on carbon in CO2 is __________. A) 1 B) 2 C) 3 D) 1 E) 0 17) Which one of the following molecules has a non-zero dipole moment? A) BeCl2 B) Br2 C) BF3 D) IBr E) CO2 18) The molecular geometry of the CS2 molecule is __________. A) tetrahedral B) linear C) T shaped D) bent E) trigonal planar 19) According to valence bond theory, which orbitals on hydrogen atoms overlap in the formation of the bond in H2? A) 1s B) 1p C) 2s D) 2p E) 3d 20) The hybridization of orbitals on the central atom in a molecule is sp2. The electron domain geometry about this central atom is __________. A) trigonal planar B) tetrahedral C) linear D) octahedral E) trigonal bipyramidal 21) In order to produce sp3 hybrid orbitals, __________ s atomic orbital(s) and __________ p atomic orbital(s) must be mixed. A) one, three B) two, two C) two, three D) one, two E) one, one 22) There are __________ σ and __________ π bonds in the H2CCCH2 molecule. A) 6, 4 B) 4, 2 C) 2, 2 D) 2, 6 E) 6, 2 23) There is/are __________ π bond(s) in the molecule below. A) 0 B) 1 C) 2 D) 4 E) 16 SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. 24) (3 pts) What is the energy (J) of a green photon of light that has wavelength of 532 nm? 2 (h  6.626 x 10 34 J s) 25) (3 pts) Explain the main observation about the H emission spectrum and what new theory concerning the structure of the atom is inspired. 26) (2 pts) What is the condensed electronic configuration aluminum (Al) and indicate how many core electrons it has and how many valence electrons it has. ¡ 27) (8 pts) (True or False) a. A neon atom in its ground state will be diamagnetic. . . b. Each shell (principal energy level) of quantum number n contains n subshells. . c. For all atoms of the same element, the 2s orbital is larger than the 1s orbital. d. An electron in a 3p orbital could have a value of 2 for its angular momentum quantum number(l). . 28) (2 pts) (Circle the right choice) Halogens are very reactive because they ARE / ARE NOT very electronegative. 29) (3 pts) Briefly describe the characteristics of a covalent bond 30) (9 pts) Draw the Lewis structure for C2F4, CO, and SO3 (draw all resonance structures, if any). For each compound indicate the total number of electrons and the formal charge of each atom. 31) (6 pts) Predict the molecular geometry of CHCl3? Is it polar or nonpolar? 32) (2 pts) If we take away two electrons from the outer shell of calcium, it would have the same electron configuration as what element? 33) (3 pts) Describe the location of the electrons in a π bond with respect to the nuclei. 34) (8 pts) Draw a picture of the resulting orbitals when an 's' orbital hybridizes with a 'p' orbital. How many hybrid orbitals are produced? What is the 3 D shape that these orbitals have? What is the name of this hybridization? 35) (3 pts) Explain how nonbonding electrons influence the shape of molecules. 36) (2 pts) What is the difference in the electron configuration between carbon–14 and carbon–12? 3 Answer Key PRACTICE TEST 3 1) A 2) D 3) D 4) B 5) A 6) B 7) E 8) A 9) A 10) B 11) E 12) C 13) C 14) B 15) E 16) E 17) D 18) B 19) A 20) A 21) A 22) E 23) C 24) 3.74 × 10 19 J 25) The colors that were emitted were in discrete lines, not a continuum. This led to the conclusion that electrons were in quantized orbits around the nucleus and that light absorbed or emitted corresponded to distinct jumps between these energy levels. This was the Bohr model of the atom. 26) Al : [Ne] 3s2 3p1 10 core electrons and 3 valence 27) a. True; b. True; c. True; d. True. 28) ARE 29) A covalent bond occurs between two atoms when they share electrons. Electrons in half full obitals will overlap to complete their octet and act a 'glue' to hold the nuclei together. 30) C2F4 has 36 e , all atoms have a formal charge of 0. CO has 10 e , the formal charges are: C  1 and O  1 SO3 has 24 e , the formal charges are: S  2, O  0, O  1, and O  1. 31) 4 domains, tetrahedral, polar 32) argon 33) The bonding electrons in above and below the nuclei. 34) 2 orbitals are produced. The hybridization is an 'sp' hybrid. 35) Nonbonding electrons take up more space than bonding electrons and act to compress the bond angles of the other electron domains. 36) There is no difference. ¡ 4 ...
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This note was uploaded on 02/10/2011 for the course CHEM 201 taught by Professor Griffen during the Fall '09 term at Bunker Hill.

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