Discussion:
Bonding, Lewis Structures and Molecular Geometry
1. Consider the following elements and arrange them in order of increasing number of electrons depicted in electron dot symbols. Which one occupies the intermediate position in the series? P, Se, Si, I and B
A. P
B. B
C. Si
D. I
2. Consider the following elements and select the one which has the smallest number of electrons shown in an electron dot symbol. Al, Se, Si, Sb and Br
A. Al
B. Br
C. Si
D. Sb
3. Consider the following species. Which contain an odd number of electrons? BrO3, HO2-, N2O, SO3 and SO32-
A. 2 and 5
B. only 2
C. 3 and 4
D. only 1
4. Consider the following species. Which contain an odd number of electrons? O, O2-, O22-, O2- and O3
A. only 3
B. only 2
C. 2 and 3
D. only 4
5. Consider the following species. Which contain an odd number of electrons? NO2, CO, O3-, O22- and SO2
A. 2 and 4
B. 2 and 5
C. 2, 4 and 5
D. 1 and 3
6. The ion, CS32- consists of a central carbon atom bonded to the three other atoms. Write a resonance form conforming to the Lewis octet rule and determine the number of double bonds in this species.
A. zero
B. three
C. two
D. one
7. Write resonance structures for SO2 and SO3. Based on these structures one can conclude that
A. both have the same bond length
B. SO2 has longer bonds than SO3
C. SO2 has shorter bonds than SO3
D. bond lengths are variable in both compounds
8. What types of hybrid orbitals are involved in bonding of BH4-?
A. sp
B. sp2
C. sp3
D. dsp3
9. What types of hybrid orbitals are involved in bonding of BCl3?
A. sp
B. sp2
C. sp3
D. dsp3
10. Which of the species in the following list is tetrahedral?
BF4-
SF4
XeF4
SiF4
A. 1 and 3
B. 1 and 4
C. 1 only
D. 2 and 3
11. Which of the species in the following list is square planar?
BF4-
SF4
XeF4
SiF4
A. 2 and 3
B. 3 only
C. 1 only
D. 1 and 4
12. Which of the following molecules is nonlinear?
A. HCN
B. C2H2
C. SO2
D. CO2
13. The largest of the following species is:
A. As3-
B. Se2-
C. S2-
D. Br-
14. Draw the Lewis formula for IF2+. How many lone pair(s) of electrons are there in the valence shell of the central atom?
A. 0
B. 1
C. 2
D. 3
15. Draw the Lewis formula for NF4+. How many lone pair(s) of electrons are there in the valence shell of the central atom?
A. 0
B. 1
C. 2
D. 3
16. The bond angles in IF4- are:
A. slightly less than 109.5º
B. slightly less than 90º
C. exactly 109.5º
D. exactly 90º
17. The bond angles in IF2+ are:
A. exactly 109.5º
B. exactly 120º
C. slightly less than 90º
D. slightly less than 109.5º
18. Calculate the Ho for the following reaction using the given bond energies. (H-Cl = 431 kJ; O-O = 494 kJ; H-O = 463, Cl-Cl = 243).
4 HCl(g) + O2(g) → 2 H2O(g) + 2 Cl2(g)
A. -102
B. -120
C. -139
D. -152
19. Use the following bond energies to calculate Ho for the given reaction. (H - C = 414; C - C = 347; C = C = 619; H - O = 464; C - O = 351).
CH3CH3(g) + H2O(g) → CH3CH2OH(g)
A. -22
B. -33
C. -45
D. -56
20. Calculate the Ho for the following reaction using the given bond energies. (C - H = 414 kJ; F - F = 155 kJ; H - F = 431, C - F = 485).
CH4(g) + 4 F2(g) → CF4(g) + 4 HF(g)
A. -1388
B. -1422
C. -1542
D. -1598