8TQ: Basic Concepts of Chemical Bonding
Name: ________________________
Text Questions from Brown, et. al.
1. The atoms in the carbonate ion (and polyatomic ions generally) are held to each other by ___________
bonds, while the carbonate ion is bonded to cations by _______ bonds.
8.1
2. When is there a chemical bond between two species?
3. Ionic bonds are ______________ forces that exist between ______ of _____________ charge. Ions are
formed by the transfer of __________. Ionic substances generally result from _______ interacting with
_______________.
4. A. Covalent bonds result from what?
B. Covalent bonds typically occur between…
5. A. In a metallic bond, each atom is bonded…
B. In metals, the bonding electrons are…
6. Of what does a Lewis symbol for an element consist?
7. Where may dots be placed around an element’s symbol in a Lewis symbol?
8. Of what does an octet consist?
8.2
9. During electron transfer, the atom with a ____ _____________ ________ gives up an electron, while an
atom with a _____ __________ ___________ gains it.
10. The lattice energy is a measure of how much…
11. Although ionization energies are endothermic, why is the formation of ionic compounds an exothermic
process?
12. For a given arrangement of ions, the lattice energy increases…
13. Why do we find that ionic compounds usually have cations with a charge of up to 3+ only?
14. Do transition elements usually form ions having a noble-gas configuration?
15. In forming ions, transition metals lose the _________-_______ ___ electrons first, then as many ___
electrons as are required.
8.3
16. The properties of ionic substances – brittleness, high melting points, crystalline – are due to
electrostatic forces that…
17. The atoms in H2 are held together principally because…
18. In a Lewis structure, how do we show... …an electron pair that is shared between atoms?
…an unshared pair?
19. A single bond is _____ shared pair of electrons (i.e., _____ electrons). A double bond is _____ shared
pairs of electrons (i.e., ______ electrons). A triple bond is _______ shared pair of electrons (i.e., ____
electrons).
20. What happens to the bond length as the number of shared pairs increases?
8.4
21. How are electrons shared in a…
…nonpolar covalent bond?
…polar covalent bond?
22. What kind of bond is formed if the electronegativity difference is large enough?
23. What is electronegativity?
24. The greater an atom’s electronegativity, the greater is its…
25. The most electronegative element is ___________, which has an electronegativity value of ____. The
least electronegative element is __________, which has a value of _____.
26. In general, what results when the electronegativities of the bonded atoms are equal?
27. The greater the difference in electronegativities between two atoms…
28. Write two ways to indicate the polarity of the HF molecule.
29. Besides aligning themselves with respect to each other, polar molecules are also attracted to ______.
30. Is there a well-defined separation or is there a continuum between ionic and covalent bonding?
31. With covalent bonding, we expect compounds to exist as ____________, to have properties such as
_____ melting and boiling points, and to exhibit _________________ behavior in solution. With ionic
bonding, we expect compounds to exist with _________ _______ structures, to be ________, to have
______ melting points, and to exhibit strong _____________ behavior.
32. What is the simplest approach one can take with regard to ionic and covalent interactions?
33. A more sophisticated approach is to use what?
34. In bonds between metals and nonmetals, you should expect a significant degree of covalency when…
8.5
35. To draw Lewis structures…
A. Sum the __________ electrons from all the atoms. _____ one electron for each net ____________
charge and _____________ one electron for each ____________ charge.
B. Write symbols of the atoms, showing which are connected to which by a _________ _______.
C. Complete the _________ around the atoms bonded to the central atom.
D. Place any extra electrons…
E. If the central atom doesn’t have an octet, try…
36. In calculating formal charge, which electrons are assigned to a given atom?
37. For an ion, what does the formal charge equal?
38. In choosing the correct Lewis structure, we choose the one in which…
8.6
39. In a ____________ __________, the placement of the ______ is the same, but that of the ________ is
different.
40. Do molecules oscillate between various resonance structures?
41. The true arrangement of electrons in molecules with resonance structures is a _________ of multiple
Lewis structures.
42. Draw the resonance in benzene using a double-headed arrow. Then draw the shorthand notation.
8.7
43. Exceptions to the octet rule can occur in species: A.
B.
C.
44. “Less than an octet” often occurs with compounds with the elements ________ or _______________.
45. The B atom in BF3 is shown in BF3’s Lewis structure with six electrons around it. What about BF 3’s
reactivity prompts us to write only six electrons around B?
46. What do third-period elements use to help them exceed an octet?
47. Exceeding an octet is more likely if the central atom is ________ and if the exterior atoms are _______.
48. When choosing between alternative Lewis structures, the structure that is preferred is the one…
8.8
49. How is the strength of the covalent bond between two atoms determined?
50. Why is bond enthalpy always a positive quantity?
51. On the other hand, when a bond forms, energy is always…
52. Using average bond enthalpies to estimate the enthalpies of reactions allows us to quickly estimate…
53. Write the equation to use in estimating the enthalpy of a reaction.
54. What happens to a bond as the number of bonds between two atoms increases?