Download Problem Set III The Shape of Molecules 1) Draw the Lewis structure

SCE 3401
Inorg. Chem.
Problem Set III
The Shape of Molecules
1) Draw the Lewis structure with lowest formal charges (if any), and determine the
charge of each atom in; (a) OCS; (b) NO. (c) IF5 (d) ClO–
2) These species do not obey the octet rule. Draw a Lewis structure for each of the
following: (a) BrO4– (b) HNO3 (c) ICl2– (d) SbF4–
3) Name the shape and give the AXmEn classification and ideal bond angle(s) for each of
the following general molecules:
4) Name the shape and give the AXmEn classification and ideal bond angle(s) for each of
the following general molecules:
5) Determine the electron-group arrangement, molecular shape, and ideal bond angle(s)
for each of the following:
(a) O3
(b) H3O+
(c) NF3
(d) SO42–
(e) NO2–
(f) PH3
(g) SO3
(h) N2O
(i) CH2Cl2
6) Arrange the following AFn species in order of increasing F¬A¬F bond angles: BF3,
BeF2, CF4, NF3, OF2.
7) State an ideal value for each of the bond angles in each molecule.
(d)
8) Which molecule in each pair has the greater dipole moment? Give the reason for your
choice.
(a) SO2 or SO3
(b) ICl or IF
(c) SiF4 or SF4
(d) H2O or H2S
Problem set 3 | page 1
SCE 3401
Inorg. Chem.
9) There are three different dichloroethylenes (molecular formula C2H2Cl2), which we can
designate X, Y, and Z. Compound X has no dipole moment, but compound Z does.
Compounds X and Z each combine with hydrogen to give the same product:
C2H2Cl2 (X or Z) + H2 → ClCH2—CH2Cl
What are the structures of X, Y, and Z? Would you expect compound Y to have a dipole
moment?
10) Chloral, Cl3C—CH=O, reacts with water to form the sedative and hypnotic agent
chloral hydrate, Cl3C—CH(OH)2. Draw Lewis structures for these substances, and
describe the change in molecular shape, if any, that occurs around each of the carbon
atoms during the reaction
11) When XeF4 is reacted with a solution of water in CH3CN solvent, the product
F2OXeN≡CCH3 is formed. Applying a vacuum to crystals of this product resulted in
slow removal of CH3CN:
F2OXeN≡CCH3 → XeOF2 + CH3CN
Propose the structure for XeOF2 and F2OXeN≡CCH3
(Brock, D. S.; Bilir, V.; Mercier, H. P. A.; Schrobilgen, G. J. J. Am. Chem. Soc. 2007, 129, 3598.)
12) Which member of each pair of compounds forms intermolecular H bonds? Draw the
H-bonded structures in each case:
13) What type(s) of the strongest intermolecular forces exist between each of the
following molecules?
(a) CH3OH (b) CCl4
(c) Cl2
(d) H3PO4
(e) SO2
(f) MgCl2
(g) CH3Cl
(h) CH3CH3 (i) NH3
(j) Kr
(k) BrF
(l) H2SO4
14) Which substance has the lower boiling point? Explain.
(a) LiCl or HCl
(b) NH3 or PH3
(c) Xe or I2
(d) NaBr or PBr3
(e) H2O or HBr
The weaker the intermolecular forces, the lower the boiling point.
15) Which substance has the higher boiling point? Explain.
a) CH3CH2OH or CH3CH2CH3
(b) NO or N2
(c) H2S or H2Te
(d) FNO or ClNO
Problem set 3 | page 2