CHAPTER 8 SEC 8.4
Chemical Bonds
CH 8 SEC 8.4 DETERMINATION OF BOND
TYPE?
Bond type:
difference in electronegativity?
 Ionic :
3.3 – 1.7 range of diff. EN
 Polar covalent :
.3 – 1.7
 Nonpolar covalent:
0 - .3
 Ch 6 table 6.2 for EN values for all atoms
 p.151 red book in class
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What type of bonding would be expected between
the following pairs of elements?
 a) Cl and K
 Ans. Ionic (EN diff = 3.0 - .8 = 2.2)
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b) O and H
 Ans. 3.5 – 2.1 = 1.4 polar covalent
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c) O and O
 Ans. 3.5 – 3.5 = 0 nonpolar covalent
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CW: FILL IN THE FOLLOWING CHART WITH A
PARTNER – ONE PAPER, TWO NAMES, EVERY OTHER
LINE SWITCH WHO WRITES ANSWER.  WAIT TO TURN
IN…SHARING AT END
bonding between: EN diff.: Bond type: More EN atom:
1. Na and Br
2. Ti and O
3. N and N
4. C and O
5. Ba and O
6. P and O
7. Ca and Cl
8. Be and F
9. S and Cl
10. N and O
INTERMOLECULAR FORCES
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Forces of attraction between molecules (weaker than
either ionic or covalent bonds)
van der Waals forces are the weakest attractions
between molecules (two types: dispersion forces &
dipole interactions)
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Hydrogen bonding – “Not a true bond”
The intermolecular force in which a hydrogen atom
that is bonded to a highly electronegative atom is
attracted to an unshared pair of electrons of an
electronegative atom in a nearby molecule.
Ex/ water molecules:
dipole-interactions: Forces of attraction
between polar molecules.
 Ex/ammonia

London Dispersion forces: forces of attraction
between nonpolar atoms or molecules that are
created by temporary dipoles.
 ex/ Noble gases

STRONGEST TO WEAKEST
1. Metallic bonding
 2. Covalent bonding
 3. Ionic bonding
 4. hydrogen bonding (force of attraction, not a
bond)
 5. dipole-interactions (force of attraction btw
polar molecules)
 6. London dispersion (force of attraction btw
nonpolar atoms – noble gases)

CH 8 REVIEW
1. The following molecules contain polar bonds.
The only nonpolar molecule is: HCl, H2O, CO2,
NH3
 2. A polar molecule contains ______________.
 3. What is the Lewis structure of HCl?
 4. The following molecules contain polar bonds.
The only polar molecule is: CCl4, CO2, NH3, CH4
 5. Atoms are __________ when they are
combined.
 6. In a molecule of fluorine, the two shared
electrons give each fluorine atom _____ electrons
in their outer energy level.
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7. In which of the following is NOT a nonpolar
covalent bond? HCl, O2, Cl2, H2
 8. In metals, the valence electrons
________________________.
 9. In drawing Lewis structure, the central atom
is the ______________________________.
 10. In drawing a Lewis structure, each nonmetal
atom except H should be surrounded by _____
electrons.
 11. What is the correct Lewis structure for CCl4 ?
 12. As independent particles, atoms are ______.
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13. VSEPR theory is a model for
predicting_________________.
 14. If the atoms that share electrons have an
unequal attraction for the electrons the bond is
called _______________.
 15. The chemical formula for water is H2O.
What type of formula is that?
 16. The mixing of two or more atomic orbitals of
similar energies on the same atom to produce
new orbitals of equal energies is called ________.
 17. The shiny appearance of metals is due to
________________.
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18. The elements of the ______ group satisfy the
octet rule without forming compounds.
 19. According to VSEPR theory what is the
shape of ammonia, NH3 ?
 20. Use VSEPR theory to predict the shape of
HCl?
 21.The electrons involved in the formation of a
chemical bond are called __________________.
 22. In the crystal lattice of an ionic compound,
each cation is surrounded by _______________.
 23. Malleability and ductility are properties of
________ bonds.
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24. Shifting layers in an ionic compound causes it to
___________________.
25. A chemical bond results from the mutual
attraction of the nuclei of atoms and _________.
26. A covalent bond results when ________ are
shared.
27. The B-F bond in BF3 (electronegativity for B is
2.0 and F is 4.0) is _________________.
28. A neutral group of atoms held together by
covalent bonds is a __________________.
29. Which of the following is NOT an example of a
molecular formula? B, O2, Cl2, H2, H2O
30. How many double bonds are in the Lewis
structure for HF, hydrogen fluoride?
31. How many extra electrons are in the Lewis
structure of the sulfate ion, SO42- ?
 32. A chemical bond that results from the
electrostatic attraction between cations and
anions is called a(n)____________________.
 33. An octet is equal to ______ electrons.
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The End
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