IB Chemistry I. Topic 4 (Bonding) Review
1. What is the correct formula of cerium(III) phosphate?
2. What is the formula of magnesium fluoride?
3. The electronegativities of four different elements are given below (the letters are not their chemical symbols).
W
X
Y
Z
Element
0.9
1.2
3.4
4.0
Electronegativity
Based on this information which atoms could form an ionic bond?
4. What are the correct formulas of the following ions?
Ammonium
Hydrogencarbonate
Phosphate
+
2–
A.
NH4
HCO3
PO4–
B.
NH3+
HCO3–
PO43–
C.
NH4+
HCO32–
PO42–
D.
NH4+
HCO3–
PO43–
5. What happens when magnesium metal reacts with chlorine gas?
A. Each magnesium atom loses two electrons and each chlorine atom gains two electrons.
B. Each magnesium atom gains one electron and each chlorine atom loses one electron.
C. Each magnesium atom loses two electrons and each chlorine atom gains one electron.
D. Each magnesium atom gains one electron and each chlorine atom loses two electrons.
6. Which is the best description of ionic bonding?
A. The electrostatic attraction between positively charged nuclei and an electron pair
B. The electrostatic attraction between positive ions and delocalized negative ions
C. The electrostatic attraction between positive ions and delocalized electrons
D. The electrostatic attraction between oppositely charged ions
7. Which statements best describe the structure of sodium chloride, NaCl?
I. Each sodium ion is surrounded by six chloride ions.
II. The chloride ions are arranged octahedrally around each sodium ion.
III. The lattice forms a cubic structure.
8. Metal “M” has only one oxidation number (ionic charge) and forms a compound with the formula MCO3.
Which formula is correct?
A. MNO3
B. MNH4
C. MSO4
D. MPO4
9. Describe the structure and bonding in silicon dioxide and carbon dioxide.
10. What compound is formed when lithium reacts with selenium?
11. What type of solid materials are typically hard, have high melting points and poor electrical conductivities?
I.
Ionic
II.
Metallic
III.
Covalent-network (these are the giant, macro-molecules)
12. Which particles are responsible for electrical conductivity in metals?
13. Which compound forms hydrogen bonds in the liquid state?
A. C2H5OH
B. CHCl3
C. CH3CHO
D. (CH3CH2)3N
14. Describe and compare three features of the structure and bonding in the three allotropes of carbon: diamond,
graphite and C60 fullerene.
15. Draw the Lewis structure of CO2 and predict its shape and bond angle.
16. Describe the structure and bonding in SiO2.
17. Explain why silicon dioxide is a solid and carbon dioxide is a gas at room temperature.
18. Describe the bonding within the carbon monoxide molecule.
19. The Lewis structure of SO2 is given below.
.. ..
: O ―S O :
..
..
What is the shape of the SO2 molecule? Bond angles?
20. Explain the electrical conductivity of molten sodium oxide.
21. Which molecule has a non-bonding pair of electrons on the central atom?
A. BF3
B. SO2
C. CO2
D. SiF4
22. When C2H2, C2H4 and C2H6 are arranged in order of increasing carbon-carbon bond strength (weakest
bond first), what is the correct order?
23. Ammonia, NH3, is a weak base. Draw the Lewis structure of ammonia and state the shape of the molecule
and its bond angles.
24. The conjugate acid of ammonia is the ammonium ion, NH4+. Draw the Lewis structure of the ammonium ion
and deduce its shape and bond angles.
25. Which molecule has the shortest carbon-oxygen bond length?
A. CH3COOH
B. CH3CH2OH
C. CO2
D. CO
26. Which statement about the bonding between carbon atoms is correct?
A. In C60 fullerene each carbon atom is covalently bonded to three other carbon atoms.
B. In C60 fullerene each carbon atom is covalently bonded to four other carbon atoms.
C. In graphite each carbon atom is covalently bonded to four other carbon atoms.
D. In graphite each carbon atom forms a double covalent bond with three other carbon atoms.
27. Which intermolecular forces exist between molecules of carbon monoxide, CO?
28. What is the shape of the ammonia molecule, NH3? Bond angles?
29. Which molecule is polar?
A. CH2Cl2
B. BCl3
C. Cl2
D. CCl4
30. Which compound has a covalent macromolecular (giant covalent) structure?
A. MgO(s)
B. Al2O3(s)
C. P4O10(s)
D. SiO2(s)
31. Which species have a dative covalent bond?
I. CO
II. NH3
III. H3O+
A.
I and II only
B.
I and III only
C.
II and III only
D.
I, II and III
32. Which order is correct when the following compounds are arranged in order of increasing melting point?
A. CH4 < H2S < H2O
B. H2S < H2O < CH4
C. CH4 < H2O < H2S
D. H2S < CH4 < H2O
33. Ethene, C2H4, and hydrazine, N2H4, are hydrides of adjacent elements in the periodic table.
(a)
(i)
Draw Lewis (electron dot) structures for C2H4 and N2H4 showing all valence electrons.
(ii) State and explain the H–C–H bond angle in ethene and the H–N–H bond angle in hydrazine.
(b)
The polarity of a molecule can be explained in terms of electronegativity.
(i) Define the term electronegativity.
(ii) Compare the relative polarities of the C–H bond in ethene and the N–H bond in hydrazine.
(iii) Hydrazine is a polar molecule and ethene is non-polar. Explain why ethene is non-polar.
(c)
The boiling point of hydrazine is much higher than that of ethene. Explain this difference in terms
of the intermolecular forces in each compound.
34. Draw the Lewis structures for carbon monoxide, CO, carbon dioxide, CO2 and methanol, CH3OH.
List, with an explanation, the three compounds in order of increasing carbon to oxygen bond length
(shortest first).
35. Predict the shape and bond angles for the following species:
(i) CO2
(ii) CO32–
(iii) BF4–
36. State what best describes metallic bonding.
37. Explain, using diagrams, why CO and NO2 are polar molecules but CO2 is a non-polar molecule.
38. Describe the structure and bonding in silicon dioxide.
39. PF3, SF2 and SiF4 have different shapes. Draw their Lewis structures and use the VSEPR theory to predict
the name of the shape of each molecule.
40. What is the correct order if the compounds are arranged in order of increasing boiling point?
A. CH4 < CH3Cl < SiH4 < CH3OH
B. CH3OH < CH4 < CH3Cl < SiH4
C. CH3OH < CH3Cl < SiH4 < CH4
D. CH4 < SiH4 < CH3Cl < CH3OH
41. How many atoms is each carbon directly bonded to in its allotropes?
42. (i) Outline the principles of the valence shell electron pair repulsion (VSEPR) theory.
(ii) Use the VSEPR theory to deduce the shape of H3O+ and C2H4. For each species, draw the Lewis
structure, name the shape, and state the value of the bond angle(s).
(iii) Predict and explain whether each species is polar.
(iv) Using Table 7 of the Data Booklet (electronegativity), predict and explain which of the bonds O-H, O-N
or N-H would be most polar.
43. Predict and explain which of the following compounds consist of molecules (meaning covalently bonded):
NaCl, BF3, CaCl2, N2O, P4O6, FeS and CBr4.
44. Diamond, graphite and C60 fullerene are three allotropes of carbon.
(i) Describe the structure of each allotrope.
(ii) Compare the bonding in diamond and graphite.
45. Predict the shape of a molecule of AsH3
46. If the electronegativity difference between two is greater than 1.7 or so, what type of bond will they form?
47. What is the shape of a molecule of carbon tetrachloride, CCl4?
48. How many valence electrons will hydrogen share in a bond?
49. If a molecule has three electron domains (negative charge centres) around its center atom and two of those are bonds
and pair is non-bonded, what is the name of its shape?
50. What is a molecule called that is composed of two identical atoms covalently bonded?
a. Would it be polar?
i. Why or why not?
51. Do molecules (covalent) tend to have lower or higher melting points than ionic compounds? Why?
52. Will the molecule CF4 dissolve in water?
b. Why or why not?
53. Why do atoms share electrons in covalent bonds?
54. What causes water molecules to have a bent shape, according to VSEPR theory?
55. According to VSEPR theory, if there are three electron domains (negative charge centres) all involved in bonds in
the valence shell of an atom, they will be arranged in a(n) __________ geometry.
56. The molecular geometry of BrO2 is _________.
57.
58.
59.
60.
61.
62.
63.
64.
65.
66.
-
The molecular geometry of the BrO3 ion is __________.
The molecular geometry of the left-most carbon atom in the molecule is ____. The second carbon ______
An electron domain (electron centres) consists of __________
According to VSEPR theory, if there are three electron domains on a central atom, they will be arranged such that
the shape will be __________.
A molecule has the formula AB3 and the central atom is in a different plane from the surrounding three atoms. Its
molecular shape is __________.
Elemental iodine (I2) is actually a solid at room temperature. What is the major attractive force that exists among
different (I2) molecules in the solid?
Hydrogen bonding is a special case of __________.
Describe where the valence electrons in metals are. What properties does this give most metals?
How do the bond angles in CH4, NH3 and H2O compare?
Which combination of the characteristics of element X, a metal, and element Y, a non metal, is most likely to
lead to ionic bonding?
67.
A.
B.
C.
D.
68.
69.
70.
71.
72.
73.
74.
75.
76.
77.
X
low ionization energy
low ionization energy
high ionization energy
high ionization energy
Y
high electronegativity value
low electronegativity value
high electronegativity value
low electronegativity value
Which particles are responsible for electrical conductivity in metals?
Explain why sodium oxide has a higher melting point than sulfur trioxide.
Do van der Waals’ forces increase or decrease going down a group on the periodic table? Explain.
As far as van der Waals’ forces are concerned, what shapes of molecules have a higher boiling point?
What types of molecules or compounds can conduct electricity and why?
Explain the concept of “like dissolves like”.
What type of molecules have the highest melting point?
Explain why the melting points of the elements decrease down group 1 and increase down group 7.
Explain the increase in the melting point from sodium to aluminium.
Explain why sodium conducts electricity but phosphorus does not.