Basic Concepts of Chemical Bonding Test (Answer Key Part 3)

30) What is the maximum number of triple bonds that a carbon atom can form? A) 4 B) 1 C) 0 D) 2 E) 3 Answer: B 31) In the molecule below, which atom has the largest partial negative charge? Cl ∣ F— C —Br ∣ I A) Cl B) F C) Br D) I E) C Answer: B 32) The ability of an atom in a molecule to attract electrons is best quantified by the ________. A) paramagnetism B) diamagnetism C) electronegativity D) electron charge-to-mass ratio E) first ionization potential Answer: C 33) Given the electronegativities below, which covalent single bond is most polar? Element: H C N O Electronegativity: 2.1 2.5 3.0 3.5 A) C—H B) N—H C) O—H D) O—C E) O—N Answer: C 34) Electronegativity ________ from left to right within a period and ________ from top to bottom within a group. A) decreases, increases B) increases, increases C) increases, decreases D) stays the same, increases E) increases, stays the same Answer: C 35) Electropositivity ________ from left to right within a period and ________ from top to bottom within a group. A) decreases, increases B) increases, increases C) increases, decreases D) stays the same, increases E) increases, stays the same Answer: A 36) A nonpolar bond will form between two ________ atoms of ________ electronegativity. A) different, opposite B) identical, different C) different, different D) similar, different E) identical, equal Answer: E 37) The ion ICl4- has ________ valence electrons. A) 34 B) 35 C) 36 D) 28 E) 8 Answer: C 38) The ion NO- has ________ valence electrons. A) 15 B) 14 C) 16 D) 10 E) 12 Answer: E 39) The ion PO43- has ________ valence electrons. A) 14 B) 24 C) 27 D) 29 E) 32 Answer: E 40) The Lewis structure of AsH3 shows ________ nonbonding electron pair(s) on As. A) 0 B) 1 C) 2 D) 3 E) This cannot be determined from the data given. Answer: B 41) The Lewis structure of PF3 shows that the central phosphorus atom has ________ nonbonding and ________ bonding electron pair(s). A) 2, 2 B) 1, 3 C) 3, 1 D) 1, 2 E) 3, 3 Answer: B 42) The Lewis structure of HCN (H bonded to C) shows that ________ has ________ nonbonding electron pair(s). A) C, 1 B) N, 1 C) H, 1 D) N, 2 E) C, 2 Answer: B 43) The formal charge on carbon in the molecule below is ________. A) 0 B) +1 C) +2 D) +3 E) -1 Answer: A 44) The formal charge on nitrogen in NO3- is ________, where the Lewis structure of the ion is: A) -1 B) 0 C) +1 D) +2 E) -2 Answer: C 45) The formal charge on sulfur in SO42- is ________, where the Lewis structure of the ion is: A) -2 B) 0 C) +2 D) +4 E) -4 Answer: B 46) In the Lewis structure of ClF, the formal charge on Cl is ________, and the formal charge on F is ________. A) -1, -1 B) 0, 0 C) 0, -1 D) +1, -1 E) -1, +1 Answer: B 47) In the Lewis structure of HCO3-, the formal charge on H is ________, and the formal charge on C is ________. A) -1, -1 B) 0, 0 C) 0, -1 D) +1, -1 E) -1, +1 Answer: B 48) In the resonance form of ozone shown below, the formal charge on the central oxygen atom is ________. A) 0 B) +1 C) -1 D) +2 E) -2 Answer: B 49) How many equivalent resonance forms can be drawn for CO32-? (Carbon is the central atom.) A) 1 B) 2 C) 3 D) 4 E) 0 Answer: C 50) How many equivalent resonance forms can be drawn for the nitrate ion? A) 0 B) 2 C) 3 D) 4 E) 1 Answer: C 51) How many equivalent resonance structures can be drawn for the molecule of SO3 without having to violate the octet rule on the sulfur atom? A) 5 B) 2 C) 1 D) 4 E) 3 Answer: E 52) How many different types of resonance structures can be drawn for the ion SO32-? A) 1 B) 2 C) 3 D) 4 E) 5 Answer: C 53) Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. Bond: D (kJ/mol): A) +160 B) -160 C) -217 D) -63 E) +63 Answer: C C≡C 839 C-C 348 H-I 299 C-I 240 C-H 413 54) Using the table of average bond energies below, the ΔH for the reaction is ________ kJ. H-C≡C-H (g) + H-Cl (g) → H2C CHCl (g) Bond: C≡C C=C H-Cl C-Cl C-H D (kJ/mol): 839 614 431 328 413 A) +741 B) -85 C) -839 D) -741 E) +85 Answer: B 55) Using the table of average bond energies below, the △H for the reaction is ________ kJ. H3C-O-H (g) → C≡O (g) + 2H2 (g) Bond: C-O C=O C≡O C-H H-H D (kJ/mol): 358 799 1072 413 436 A) +276 B) -276 C) +116 D) +735 E) -116 Answer: C O-H 463 56) Using the table of bond dissociation energies, the ΔH for the following gas-phase reaction is ________ kJ. A) -44 B) 38 C) 304 D) 2134 E) -38 Answer: A