Name_____________________________
1. State the type of bonding- ionic (I), polar covalent (PC), nonpolar covalent (NC) or
metallic (M)- you would expect in
a) FeCl3 (s)
d) O2(g)
b) Ag (s)
e) BrCl(g)
c) CO(g)
f) RbCl(s)
2. Rank the ions in order of increasing size: Na+, Mg2+, F-.
3. Draw Lewis structures for each of the following compounds. Label each molecule as
either polar or nonpolar. Use effective charges to support your answer.
SiCl4
H2O
CH2O
CO2
4. Draw all resonance structures for carbonate ion
5. Use bonding principles regarding the octet rule and orbitals to determine if each of the
following exists. Justify your answer in each case.
a) NF5
b) AsF5
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6. Consider the reaction: 4NH3(g) + 5O2(g)  4NO(g) + 6H2O(g)
Compound Hof
(kJ/mol)
NH3(g)
-46
NO(g)
90
H2O(g)
-242
Bond
kJ/mol
N-H
O-O
O=O
N-O
N=O
N≡O
O-H
391
146
495
?
?
?
467
a) Use the Table above to determine the standard heat of reaction in kJ per mole of
NH3 combusted.
b) Using your answer in (a), the table above, and your knowledge of molecular
structure, find the bond energy, in kJ per mole, of the correct N-to-O bond.
7. Answer the following questions about the element selenium, Se.
(a) Samples of natural selenium contain six stable isotopes. In terms of atomic
structure, explain what these isotopes have in common, and how they differ.
(b) Write the complete electron configuration (e.g., 1s2 2s2... etc.) for a selenium atom
AND ion in the ground state.
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(c) Indicate which is larger, the selenium atom or the selenium ion. Justify your answer
in terms of protons and electrons.
(d) Determine the following for SeF4.
Lewis Structure:
Bond Polarity:
Molecular Polarity (Justify):
Formal Charge of each element:
Hybridization of each element:
VSEPR shape:
Sigma/Pi Bonding:
VSEPR bond angles:
8. Explain each of the following observations using principles of atomic
structure and/or bonding.
(a) Potassium has a lower first-ionization energy than lithium.
(b) The ionic radius of N3- is larger than that of O2-.
(c) A calcium atom is larger than a zinc atom.
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(d) Boron has a lower first-ionization energy than beryllium.
9. Given the following data
NH3  ½ N2 +3/2 H2
2 H2 + O2  2H2O
H= 46 kJ
H= -484 kJ
Calculate the H for 2 N2 + 6H2O  4 NH3 +3 O2
10. Write the net ionic equations for the following reactions
a. Scandium chlorate solution is mixed with a potassium oxalate solution
b. Magnesium metal is burned in oxygen
c. Hydrogen peroxide is heated
d. zinc metal is placed in a copper II chloride solution
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