1. For the following compounds draw the Lewis Structure and determine:
(a) The # of Bonding Pairs
(b) The # of Lone pairs
(c) The electron domain shape
(d) The molecular shape
(e) Hybridization
(f) Whether the molecule is polar or non-polar
SiCl
4
, PF
3
, ClF
3
, VF
5
, SiH
4
, CO, SF
2
, ClO
2
, AsO
3
, NO + , POCl
3
, ClO
4
, BeCl
2
,
NH
3
, SF
4
, BrF
3
, XeF
2
2. A substance, XY, formed from two different elements boils at -33°C. Is
XY likely to be ionic or covalent?
3. For the following compounds predict whether the bonding involved would be covalent or ionic:
(a) MnO
2
(b) P
2
S
3
(c) Cu
2
S
(d) VF
5
(e) ClF
3
4. For elements in the third row of the periodic table and beyond, the octet rule is often not obeyed. What factors are usually cited to explain this fact?
5.
Which of the following subatomic particles are most important in determining the chemical reactivity and physical properties of an atom?
•
(a) the protons
•
(b) the neutrons
•
(c) the inner (core) electrons
•
(d) the outer (valence) electrons

•
(e) none of the above
6. Arrange the following atoms in order of increasing first ionization energy:
F, He, Ge, Ca, Rb, C.
•
(a) Lowest IE Ne < Rb < Ca < C < Ge < F Highest IE
•
(b) Lowest IE Ne < Rb < Ca < Ge < C < F Highest IE
•
(c) Lowest IE Rb < Ca < Ge < C < F < Ne Highest IE
•
(d) Lowest IE Ne < F < C < Ge < Ca < Rb Highest IE
•
(e) Lowest IE Ne < Rb < Ca < Ge < C < F Highest IE
7. Predict which molecule will have the shortest C-O bond distance?
•
(a) CO
2
•
(b) H
3
COH
•
(c) CO
3
2-
•
(d) CO
2
and CO
3
2 will have C-O bonds of the same length
•
(e) the C-O bond distances will be the same in all of the above compounds
8. Use Lewis dot structures to identify which of the following molecule(s) violate the octet rule.
•
(a) PO
4
3-
•
(b) NO
•
(c) CO
2
•
(d) N
2
•
(e) the octet rule is satisfied for all four of the above molecules
9. What is the oxidation state of chlorine in ClO
2
?
•
(a) +1
•
(b) +3
•
(c) –1
•
(d) –3
•
(e) 0

10. What is the formal charge on chlorine in ClO
2
?
•
(a) +1
•
(b) +3
•
(c) –1
•
(d) –3
•
(e) 0
11. Using the following bond enthalpies as necessary:
•
C–O 358 kJ/mol H–H 436 kJ/mol
•
C=O 799 kJ/mol C–H 413 kJ/mol
•
C
≡
O 1072 kJ/mol O–H 463 kJ/mol
Estimate ∆H for the following gas phase reaction:
CO(g) + 2H
2
(g) → CH
3
OH(g)
12. Use Lewis dot structures to identify the molecule which is least likely to exist.
•
(a) XeF
4
•
(b) OF
6
•
(c) SF
6
•
(d) BeH
2
•
(e) CH
3
Cl
13. Arrange the following atoms in order of increasing electron affinity: Cl,
Ar, Si, P.
•
(a) Most positive E
A
Cl < P < Si < Ar Most negative E
A
(electron hungry)
•
(b) Most positive E
A
Ar < Cl < P < Si Most negative E
A
(electron hungry)
•
(c) Most positive E
A
Si < P < Cl < Ar Most negative E
A
(electron hungry)
•
(d) Most positive E
A
Ar < P < Si < Cl Most negative E
A
(electron hungry)
•
(e) Most positive E
A
Ar < Si < P < Cl Most negative E
A
(electron hungry)

14. Using VSEPR theory, predict the molecular shape of TeF
4
.
•
(a) tetrahedral
•
(b) see-saw
•
(c) T-shaped
•
(d) trigonal bipyramidal
•
(e) none of the above
15. Using VSEPR theory, predict the molecular shape of ClO
3
.
•
(a) tetrahedral
•
(b) trigonal planar
•
(c) T-shaped
•
(d) trigonal bipyramidal
•
(e) trigonal pyramidal
16. Which of the following molecules are polar?
•
(a) NF
3
•
(b) CCl
4
•
(c) SO
3
•
(d) CO
2
•
(e) both NF
3
and SO
3
are polar
17. Use the concept of formal charge to select the most stable resonance structure of FNC.
•
(a) F–N
≡
C
•
(b) F=N=C
•
(c) F=C=N
•
(d) F–C
≡
N
•
(e) C=F=N
18. What is the hybrid orbital set used by the phosphorous atom in the molecule PH
3
?
•
(a) sp
•
(b) sp 2
•
(c) sp 3
•
(d) sp 3 d

•
(e) sp 3 d 2
19. What is the hybridization about the carbon atoms in ethylene, H
2
C=CH
2
?
•
(a) sp
•
(b) sp
2
•
(c) sp
3
•
(d) sp
3 d
•
(e) sp
3 d
2
20. Which of the following molecules are expected to be planar (flat)?
(a) BF
3
(b) H
2
CO
(c) XeF
4
(d) H
2
CCH
2
(e) all of the above
21. How many sigma and pi bonds are there in N
2
?
22. Use Lewis dot structures to determine which of the following species contains a triple bond.
23. Use Lewis dot structures to determine which of the following molecule contains the shortest sulfur-oxygen bond.
•
(a) SO
3
•
(b) SO
3
2-
•
(c) SO
4
2-
•
(d) SO
•
(e) The shortest S-O bond is the same length in (a) and (d)
•
(a) CO
2
•
(b) C
2
H
4
•
(c) C
2
2-
•
(d) H
2
CO
•
(e) NH
3

24. Which of the following is the correct Lewis dot structure for HClO
3
?
•
(a) O(2) = Cl – O(2) – H
•
(b) O(3) – Cl(1) = O(2) – H
•
(c) O(3) = Cl = O(2) – H
•
(d) O(3) – Cl – O(2) – H
•
(e) O(3) – Cl(1) – O(2) – H
[The number in parentheses represents the number of electron pairs on the preceeding atom, for example the Lewis dot structure for water would be H -
O(2) - H. Also note that in each structure there is an oxygen ion with three non-bonding electron pairs, O(3), not shown which is bonded to the chlorine.]
25. Draw Lewis dot structures and use formal charges to determine identity of the central atom and the number of multiple bonds in CNF.
•
(a) central atom = F, 2 double bonds, 0 triple bonds
•
(b) central atom = C, 0 double bonds , 1 triple bond
•
(c) central atom = C, 2 double bonds, 0 triple bonds
•
(d) central atom = N, 2 double bonds, 0 triple bonds
•
(e) central atom = N, 0 double bonds, 1 triple bond
26. What is the oxidation state of carbon in carbon monoxide, CO?
•
(a) +4
•
(b) –1
•
(c) +2
•
(d) +1
•
(e) –2
27. What is the formal charge of carbon in carbon monoxide, CO?
•
(a) 0
•
(b) –1
•
(c) +2
•
(d) +1
•
(e) –2

28. Draw Lewis dot structures and use formal charges to determine identity of the central atom as well as the number and location of all multiple bonds in
N
2
O.
•
(a) central atom = N, one N-N triple bond,
•
(b) central atom = O, one O-N triple bond
•
(c) central atom = N, one O-N triple bond
•
(d) central atom = O, two O-N double bonds
•
(e) central atom = N, one O-N double bond and one N-N double bond
29. Which of the following diatomic molecules will be the most polar?
•
(a) N
2
•
(b) CO
•
(c) NO
•
(d) IBr
•
(e) Cl
2
30. Which of the following atoms/ions has the largest radius?
•
(a) O 2-
•
(b) Mg 2+
•
(c) Na +
•
(d) F
-
•
(e) S
2-
31. Which of the following polyatomic ions contains a double bond?
•
(a) sulfate SO
4
2-
•
(b) nitrate NO
3
-
•
(c) perchlorate ClO
4
-
•
(d) ammonium NH
4
+
•
(e) Both (a) SO
4
2-
and (b) NO
3
-
contain a double bond
32 . What is the correct electron configuration for Fe 3+ ?
•
(a) [Ar] 4s 2 3d 6
•
(b) [Ar] 3d 5
•
(c) [Ar] 4s
•
(d) [Ar] 4s
1 3d 5
2 3d 3

•
(e) [Ne] 3s 2 2d 3
1. See Attached Sheet
2. Covalent
3. (a) ionic (b) covalent (c) ionic (d) ionic (e) covalent
4. The d and f electrons allow the expansion of the octet.
5. the outer (valence) electrons
6. Lowest IE Rb < Ca < Ge < C < F < Ne Highest IE
7. CO
2
8. NO
9. +3
10. +1
11. –116 kJ
12. OF
6
13. Most positive E
A
Ar < P < Si < Cl Most negative E
A
(electron hungry)
14. see-saw
15. trigonal pyramidal
16. NF
3
17. F–C
≡
N
18. sp
3
19. sp
2

20. all of the above
21. 1 sigma and 2 pi bonds
22. C
2
2-
23. SO
24.
25. central atom = C, 0 double bonds , 1 triple bond
26. +2
27. –1
28. central atom = N, one N-N triple bond,
29. CO
30. S 2-
31. nitrate NO
3
-
32. [Ar] 3d 5