Name ____________________________________________________
Date _________________________
Covalent Bonding Review Packet
1. In which compound does the bond between the atoms have the least polar character?
(1) H2O
(2) H2S
(3) HCl
(4) HF
2. Which structural formula represents a nonpolar molecule?
(1)
(2)
(3)
(4)
3. Which molecule contains a polar covalent bond?
(1)
(2)
(3)
(4)
4. Which formula represents a molecular substance?
(1) CaO
(2) CO
(3) Li2O
(4) Al2O3
5. In a nonpolar covalent bond, electrons are
(1) located in a mobile “sea” shared by many ions (2) transferred from one atom to another
(3) shared equally by two atoms
(4) shared unequally by two atoms
6. Which molecule is nonpolar and contains a nonpolar covalent bond?
(1) CCl4
(2) F2
(3) HF
(4) HCl
7. Two atoms with an electronegativity difference of 0.4 form a bond that is
(1) ionic, because electrons are shared
(2) ionic, because electrons are transferred
(3) covalent, because electrons are shared (4) covalent, because electrons are transferred
8. The correct electron dot formula for hydrogen chloride is
(1)
(2)
(3)
9. Which combination of atoms can form a polar covalent bond?
(1) H and H
(2) H and Br
(3) N and N
(4)
(4) Na and Br
10. The bond between hydrogen and oxygen in a water molecule is classified as
(1) ionic and nonpolar
(2) ionic and polar
(3) covalent and nonpolar
(4) covalent and polar
11. A substance was found to be a soft, nonconducting solid at STP. The substance is
(1) a molecular solid
(2) a network solid
(3) a metallic solid
(4) an ionic solid
12. A solid substance conducts electricity. The bonding in the substance is
(1) metallic
(2) ionic
(3) nonpolar covalent
(4) polar covalent
13. Which molecule is nonpolar and has a symmetrical shape?
(1) HCl
(2) CH4
(3) H2O
(4) NH3
14. Hydrogen bonds are formed between molecules when hydrogen is covalently bonded to an
element that has a
(1) small atomic radius and low EN
(2) large atomic radius and low EN
(3) small atomic radius and high EN
(4) large atomic radius and high EN
15. Compared to the boiling point of H2S, the boiling point of H2O is relatively high. Which type
of bonding causes this difference?
(1) covalent
(2) hydrogen
(3) ionic
(4) network
16. Which of the following liquids has the weakest dispersion forces of attraction between its
molecules?
(1) Xe ()
(2) Kr ()
(3) Ne ()
(4) He ()
17. When calcium chloride is dissolved in water, to which end of the adjacent water molecules
will a calcium ion be attracted?
(1) oxygen end, which is the negative pole
(2) oxygen end, which is the positive pole
(3) hydrogen end, which is the negative pole (4) hydrogen end, which is the positive pole
18. Molecule-ion attractions are found in
(1) K (s)
(2) Kr (g)
(3) KCl ()
(4) KCl (aq)
19. In an aqueous solution of an ionic salt, the oxygen atom of water is attracted to the
(1) negative ion of the salt, due to the oxygen’s partial positive charge
(2) negative ion of the salt, due to the oxygen’s partial negative charge
(3) positive ion of the salt, due to the oxygen’s partial positive charge
(4) positive ion of the salt, due to the oxygen’s partial negative charge
Part 2 Questions
1. Describe the difference between ionic and covalent bonds. Include EN differences.
2. Draw electron dot diagrams to show covalent bonding for the following:
a) H2
b) CO2
c) H2O
d) NH3
3. Compare the properties of atoms held together by ionic bonds to the properties of atoms
held together by covalent bonds.
4. Determine bond polarity, molecular polarity, and shape for each of the following:
a) CH4
b) NH3
c) CO2
d) O2
e) H2O
f) HF
5. a) When you go down Group 17 or 18, why does the boiling point increase?
b) Why in Group 17 is F a gas, Br a liquid, and I a solid?
c) Why is the boiling point of H2O higher than H2S?
Answer Key
1.
2.
3.
4.
5.
2
3
3
2
3
6. 2
7. 3
8. 3
9. 2
10. 4
11.
12.
13.
14.
15.
1
1
2
3
2
16.
17.
18.
19.
4
1
4
4
Part 2
1. Ionic bonds form when electrons are transferred from metals to nonmetals. The EN
difference is greater than 1.7. Covalent bonds form when electrons are shared between
nonmetals. The EN difference is less than 1.7.
2. a)
b)
c)
d)
3. Ionic: hard crystalline structure, good conductors as liquids and in solution, but not as a
solid, high melting and boiling points, dissolve in water
Covalent: exist in all 3 phases, usually not soluble in water, solids are soft, poor conductors,
low melting and boiling points
4. a) polar bond, nonpolar molecule, tetrahedral
b) polar bond, polar molecule, trigonal pyramidal
c) polar bond, nonpolar molecule, linear
d) nonpolar bond, nonpolar molecule, linear
e) polar bond, polar molecule, bent
f) polar bond, polar molecule, linear
5. a) Moving down Group 17 or 18 increases molecular size (radius), increasing the strength of
dispersion forces which increases their boiling points.
b) Moving down a group increases molecular size (radius). F and Cl are at the top, so they
are small and therefore have weak intermolecular forces (gases). Br is bigger so
intermolecular forces are stronger, making it a liquid. I is at the bottom of the group,
making it the largest. It has the strongest intermolecular forces (a solid).
c) H2O contains hydrogen bonds which are very strong, increasing its boiling point. H 2S does
not contain hydrogen bonds (H-N,O,F).