1CHEM 107 (Fall-2006) Exam 3 (100 pts) Name: ------------------------------------------------------------------------, SSN -------------------------------- LAST NAME, First (Circle the alphabet segment of your LAST NAME): A-C D-H I-M N-R S-Z Please answer the following questions: Part I: Multiple Choices (60 pts: 15 @ 4 pts each). Circle the ONE best answer: 1. An Fe2+ ion is a) paramagnetic with four unpaired electrons b) diamagnetic with zero unpaired electrons c) paramagnetic with two unpaired electrons d) paramagnetic with one unpaired electron 2. The orbitals of 2p electrons are often represented as being a) elliptical b) tetrahedral c) dumbbell shaped d) spherical 3. Which of the following molecules is classified as predominantly ionic? a) SiO2 b) ClO2 d) P4O10 d) CaO 4. Which set of quantum numbers is correct and consistent with n = 4? a) ℓ = 3, mℓ = -3, ms = +½ b) ℓ = 4, mℓ = +2, ms = -½ c) ℓ = 2, mℓ = +3, ms = +½ d) ℓ = 3, mℓ = -3, ms = +1 5. The ground state electron configuration of iridium, Ir (Z = 77) is a) [Xe] 5d7 6s2 b) [Xe] 4f14 5d7 6s2 c) [Xe] 4f14 6d7 6s2 d) [Xe] 4f14 5d9 6. The maximum number of electrons that can occupy an orbital labeled 4px is a) 6 b) 4 c) 2 d) 3 7. The ground state electron configuration of chromium atom, Cr (Z = 24) is a) 1s2 2s2 2p6 3s2 3p6 4s2 3d4 b) 1s2 2s2 2p6 3s2 3p6 4s1 3d5 c) 1s2 2s2 2p6 3s2 3p6 3d6 d) 1s2 2s2 2p6 3s2 3p6 4s2 4p4 8. Which of the following has the highest ionization energy? a) Ar b) K c) Cl d) S29. When the three elements S, se and Cl are arranged in order of increasing atomic radius, which is the correct order? a) Se < S < Cl b) S < Cl < Se c) S < Se < Cl d) Cl < S < Se 10. Which of the following bonds is considered to be the most polar? a) O-F b) C-F c) N-F d) Si-F 11. Which of the following electromagnetic radiation has the longest wavelength? a) X-ray b) Visible light c) Radio wave d) Infrared 12. Which of the following isoelectronic species would have the largest radius? a) Mg2+ b) Na+ c) O2- d) F- 13. Which compound has a triple bond? a) O2 b) OF2 c) BeF2 d) N2 14. Compact disc players use lasers that emit red light with a wavelength of 685 nm. What is the energy of a mole of photons in kilojoule? a) 175 b) 2.9 x 10-19 c) 2.73 x 10-13 d) no answer was given 15. In the BrCN molecule there are: a) 2 σ and 1 π bonds b) 2 σ and 2 π bonds c) 3 σ and 1 π bonds d) 1σ and 3 π bonds3Part II. Calculations (12 pts) Show all work for full credit. Please express all answers with the proper units and correct number of significant figures. 1. a) Calculate the wavelength in nanometers in the H-atom spectrum that arises from the electron transition of n = 4 to n = 2. b) In what spectral region does this transition occur? -------------------------------------------------- c) Is energy absorbed or emitted? -------------------------------------------------- Part III. Bonding (28 pts): 1. (12 pts) Draw the Lewis structure for the nitrite ion, NO2+, draw the resonance structures, if there is any then: predict: a) number σ and π bonds b) The molecular shape of the ion λ (nm) Lewis Structure & resonance structures (if any) a) Molecular shape: ------------------------ b) # of σ bonds ------- and # of π bonds --------4 2. (16 pts) Draw the Lewis structure of the following molecules or ions? a) SF4 b) SO32- c) BeF2 d) PF5 a) SF4 b) SO32- c) BeF2 d) PF55 Exam 3 – Fall 2006 You will have 55 minutes to complete this exam. The exam has 4 pages plus the Periodic Table and Reference page. When you are told to do so, tear off the Periodic Table cover sheet and use as required during the exam. 1 1 H 1.01 Periodic Table of the Elements 2 He 4.00 2 3 Li 6.94 4 Be 9.01 5 B 10.816 C 12.01 7 N 14.01 8 O 16.009 F 19.0010 Ne 20.18 3 11 Na 22.99 12 Mg 24.30 13 Al 26.9814 Si 28.08 15 P 30.97 16 S 32.0617 Cl 35.4518 Ar 39.95 4 19 K 39.1 20 Ca 40.08 21 Sc 44.96 22 Ti 47.88 23 V 50.94 24 Cr 52.00 25 Mn54.9426 Fe 55.8527 Co 58.9328 Ni 58.6929 Cu 63.5530 Zn 65.3831 Ga 69.7232 Ge 72.59 33 As 74.92 34 Se 78.9635 Br 79.9036 Kr 83.80 5 37 Rb 85.47 38 Sr 87.62 39 Y 88.91 40 Zr 91.22 41 Nb 92.91 42 Mo 95.94 43 Tc (98) 44 Ru 101.145 Rh 102.946 Pd 106.447 Ag 107.948 Cd 112.449 In 114.850 Sn 118.7 51 Sb 121.8 52 Te 127.653 I 126.954 Xe 131.1 6 55 Cs 132.9 56 Ba 137.3 57 La 138.9 72 Hf 178.5 73 Ta 181.0 74 W 183.8 75 Re 186.276 Os 190.277 Ir 192.278 Pt 195.179 Au 197.080 Hg 200.681 Tl 204.482 Pb 207.2 83 Bi 209.0 84 Po (209) 85 At (210) 86 Rn (222) 7 87 Fr (223) 88 Ra 226.0 89 Ac 227.0 104 Rf (261) 105 Db (262) 106 Sg (263) 107 Bh (262) 108 Hs (265) 109 Mt (266) 110 Uun(269) 111 Uuu(272) 112 Uub(277) 58 Ce 140.1 59 Pr 140.9 60 Nd 144.2 61 Pm(145) 62 Sm 150.463 Eu 152.064 Gd 157.265 Tb 158.966 Dy 162.567 Ho 164.968 Er 167.3 69 Tm 168.9 70 Yb 173.071 Lu 175.0 90 Th 232.0 91 Pa 231.0 92 U 238.0 93 Np 237.094 Pu (244) 95 Am(243) 96 Cm(247) 97 Bk (247) 98 Cf (251) 99 Es (252) 100 Fm (257) 101 Md (258) 102 No (259) 103 Lr (260) PREFERENCE SHEET FOR CHEM 107 Equations and Constants: ν = RH/h [1/(nlo)2 – 1/(nhi)2] E = h ν c = λ ν RH = 2.180 x 10-18 J h = 6.626 x 1034 J.s c = 3.00 x 108 m/s Avogadro’s Number = 6.022 x