Sample Test Chapter 8 Bonding and Molecular Structure 1 Which combination of atoms is most likely to produce a compound with covalent bonds 2 Which of the following statements is are CORRECT 1 Ionic bonds form when one or more valence electrons are transferred from one atom to another 2 Covalent bonds involve sharing of electrons between atoms 3 In most covalently bonded compounds electrons are NOT shared equally between the atoms a K and Br b Al and S c S and Cl d Sn and F e Li and I ANS C a 1 only b 2 only c 3 only d 1 and 2 e 1 2 and 3 ANS E a 3 b 5 c 6 d 8 e 33 ANS B a 0 b 1 c 2 d 3 e 4 ANS A a b 3 An arsenic atom has valence electrons 4 How many lone pairs of electrons are assigned to the carbon atom in carbon dioxide 5 Which of the following molecules or ions are isoelectronic SO3 NF3 NO3 CO3 2 2 a SO3 and NF3 b NF3 and CO3 2 c SO3 NF3 and CO3 2 and CO3 d SO3 NO3 and CO3 e SO3 NF3 NO3 ANS D 2 6 Which of the following is a correct Lewis structure for sulfur dioxide SO2 1 c d e ANS D a 1 b 2 c 3 d 2 and 3 e 1 2 and 3 ANS D 7 Which of the following are possible Lewis structures for C2H6O 8 The central atom in SCl2 is surrounded by two single bonds and no lone pairs of electrons two single bonds and one lone pair of electrons two single bonds and two lone pairs of electrons a b c d one single bond one double bond and no lone pairs of electrons e one single bond one double bond and one lone pair of electrons ANS C 9 What is the formal charge on each atom in dichloromethane CH2Cl2 a C atom 0 each H atom 0 and each Cl atom 0 b C atom 2 each H atom 1 and two Cl atoms 0 c C atom 4 each H 1 and each Cl atom 1 d C atom 4 each H 1 and each Cl atom 1 e C atom 4 each H 1 and each Cl atom 1 ANS A 10 Which of the following are resonance structures for nitrite ion NO2 a 1 and 2 b 2 and 4 c 3 and 4 d 1 2 and 3 e 2 3 and 4 ANS A 11 Which of the following molecules or ions does not have one or more resonance structures 2 a O3 b OCN c SO2 d H2CO e NO3 ANS D a B b C c N d O e F ANS A a b ANS C 12 Which of the following elements is most likely to form a molecular structure that disobeys the octet rule 13 What is the correct Lewis structure for SF4 e c d 14 Use VSEPR theory to predict the electron pair geometry and the molecular geometry of nitrogen trichloride NCl3 a The electron pair geometry is linear the molecular geometry is linear b The electron pair geometry is trigonal planar the molecular geometry is trigonal planar c The electron pair geometry is trigonal planar the molecular geometry is bent d The electron pair geometry is tetrahedral the molecular geometry is tetrahedral e The electron pair geometry is tetrahedral the molecular geometry is trigonal pyramidal ANS E 15 Use VSEPR theory to predict the electron pair geometry and the molecular geometry of sulfur dioxide XeF4 a The electron pair geometry is tetrahedral the molecular geometry is tetrahedral b The electron pair geometry is octahedral the molecular geometry is tetrahedral c The electron pair geometry is tetrahedral the molecular geometry is octahedral d The electron pair geometry is octahedral the molecular geometry is square planar e The electron pair geometry is square planar the molecular geometry is tetrahedral ANS D 16 What are the approximate O S O bond angles in SO3 2 a 90 b 109 5 c 120 d 180 e 90 and 180 3 17 Electronegativity is a measure of the ability of a substance to conduct electricity the charge on a polyatomic cation the charge on a polyatomic anion the ability of an atom in a molecule to attract electrons to itself the oxidation number of an atom in a molecule or polyatomic anion 18 Choose which central atom in the following molecules is most electronegative 19 Use Lewis structures to predict the bond order for a sulfur oxygen bond in sulfur trioxide ANS B a b c d e ANS D a PH3 b CH4 c H2S d H2O e NH3 ANS D a 1 2 b 1 c 4 3 d 3 2 e 2 ANS C 20 One might expect PCl3 to have a trigonal planar molecular geometry since its central atom is surrounded by three outer atoms However PCl3 has a trigonal pyramidal geometry Explain ANS The shape of a molecule is dependent upon the number of electron pairs surrounding the central atom The phosphorus atom in PCl3 has four electron pairs which are distributed around the phosphorus atom in a tetrahedral geometry Thus the bond angles are approximately 109 not 120 4