Problem 36c
(c) Do you expect the O—O bond in H2O2 to be longer or shorter than the O—O bond in O2? Explain.
Problem 37
Which of the following statements about electronegativity is false? (a) Electronegativity is the ability of an atom in a molecule to attract electron density toward itself. (b) Electronegativity is the same thing as electron affinity. (c) The numerical values for electronegativity have no units. (d) Fluorine is the most electronegative element. (e) Cesium is the least electronegative element.
- (a) What is the trend in electronegativity going from left to right in a row of the periodic table? (b) How do electronegativity values generally vary going down a column in the periodic table? (c) True or false: The most easily ionizable elements are the most electronegative.
Problem 38
Problem 39
Using only the periodic table as your guide, select the most electronegative atom in each of the following sets: (a) Se, Te, Br, I; (b) Be, Mg, C, Si (c) Al, Si, P, S (d) Zn, Ge, Ga, As.
Problem 40a,b
By referring only to the periodic table, select (a) the most electronegative element in group 13; (b) the least electronegative element in the group As, Se and Br;
Problem 40d
By referring only to the periodic table, select (d) the element in the group K, C, Zn, F that is most likely to form an ionic compound with Ba.
Problem 41
Which of the following bonds are polar? (a) C—O, (b) Sl—F, (c) N—Cl, (d) C—Cl. Which is the more electronegative atom in each polar bond?
Problem 42a,b
Arrange the bonds in each of the following sets in order of increasing polarity: (a) C—F, O—F, Be—F (b) O—Cl,S—Br, C—P
Problem 42c
Arrange the bonds in each of the following sets in order of increasing polarity: (c) C—S, B— F, N — O.
Problem 43a
(a) From the data in Table 8.2, calculate the effective charges on the H atom of the HBr molecule in units of the electronic charge, e.
Problem 43b
(b) If you were to put HBr under very high pressure, so its bond length decreased significantly, would its dipole moment increase, decrease, or stay the same, if you assume that the effective charges on the atoms do not change?
- The iodine monobromide molecule, IBr, has a bond length of 249 pm and a dipole moment of 1.21 D. (a) Which atom of the molecule is expected to have a negative charge?
Problem 44
Problem 45
In the following pairs of binary compounds, determine which one is a molecular substance and which one is an ionic substance. Use the appropriate naming convention (for ionic or molecular substances) to assign a name to each compound: (a) SiF4 and LaF3 (for ionic or molecular substances) to assign a name to each compound: (b) FeCl2 and ReCl6 (c) PbCl4 and RbCl.
Problem 46a,b
In the following pairs of binary compounds, determine which one is a molecular substance and which one is an ionic substance. Use the appropriate naming convention (for ionic or molecular substances) to assign a name to each compound: (a) TiCl4 and CaF2 (b) ClF3 and VF3
Problem 46c
In the following pairs of binary compounds, determine which one is a molecular substance and which one is an ionic substance. Use the appropriate naming convention (for ionic or molecular substances) to assign a name to each compound: (c) SbCl5 and AlF3.
Problem 47a,b,c
Draw Lewis structures for the following: (a) CH2Cl2 (b) ClCN (c) SF2
Problem 47d,e
Draw Lewis structures for the following: (d) H2SO4 (H is bonded to O) (e) OF2
Problem 47f
Draw Lewis structures for the following: (f) NH2OH
- Write Lewis structures for the following: (a) H2CO (both H atoms are bonded to C), (b) H2O2, (c) C2F6 (contains a C¬C bond), (d) AsO33 - , (e) H2SO3 (H is bonded to O), (f) NH2Cl.
Problem 48
Problem 49
Which one of these statements about formal charge is true? (a) Formal charge is the same as oxidation number. (b) To draw the best Lewis structure, you should minimize formal charge. (c) Formal charge takes into account the different electronegativities of the atoms in a molecule. (d) Formal charge is most useful for ionic compounds. (e) Formal charge is used in calculating the dipole moment of a diatomic molecule.
- Write Lewis structures that obey the octet rule for each of the following, and assign oxidation numbers and formal charges to each atom: (a) OCS (b) SOCl2 (S is the central atom) (c) BrO3- (d) HClO2 (H is bonded to O)
Problem 51
Problem 52a,b,c
For each of the following molecules or ions of sulfur and oxygen, write a single Lewis structure that obeys the octet rule, and calculate the oxidation numbers and formal charges on all the atoms: (a) SO2 Write a single Lewis structure that obeys the octet rule for SO2 and assign the formal charges on all the atoms. (b) SO3 Write a single Lewis structure that obeys the octet rule for SO3 and assign the formal charges on all the atoms. (c) SO32- Write a single Lewis structure that obeys the octet rule for SO32- and assign the formal charges on all the atoms.
Problem 53b
(b) With what allotrope of oxygen is it isoelectronic?
Problem 53c
(c) What would you predict for the lengths of the bonds in NO2- relative to N¬O single bonds and double bonds?
Problem 54b
Consider the formate ion, HCO2-, which is the anion formed when formic acid loses an H+ ion. The H and the two O atoms are bonded to the central C atom. (b) Are resonance structures needed to describe the structure?
Problem 54c
Consider the formate ion, HCO2-, which is the anion formed when formic acid loses an H+ ion. The H and the two O atoms are bonded to the central C atom. (c) Would you predict that the C—O bond lengths in the formate ion would be longer or shorter relative to those in CO2?
Problem 55
Predict the ordering, from shortest to longest, of the bond lengths in CO, CO2, and CO32- .
Problem 56
Based on Lewis structures, predict the ordering, from shortest to longest, of N¬O bond lengths in NO+, NO2-, and NO3-.
- True or false: (a) The C¬C bonds in benzene are all the same length and correspond to typical single C¬C bond lengths. (b) The C¬C bond in acetylene, HC≡CH, is longer than the average C¬C bond length in benzene.
Problem 57
Problem 58a
Mothballs are composed of naphthalene, C10H8, a molecule that consists of two six-membered rings of carbon fused along an edge, as shown in this incomplete Lewis structure:(a) Draw all of the resonance structures of naphthalene. How many are there?
Ch.8 - Basic Concepts of Chemical Bonding