8.4
Describe
ionic bonding
in 1 complete
sentence.
Bond Polarity
Bonding
Ionic
Describe
covalent bonding
in 1 complete
sentence.
Covalent
Polar
Nonpolar
nonpolar covalent bond:
nonpolar covalent bond:
atoms with equal pull (similar electronegativity)
so bonding electrons are shared equally.
H2, N2, O2, F2, Cl2, Br2, I2
+
H
+
H
polar covalent bond:
bonding electrons are shared unequally.
less EN
+

more EN
H
Cl

 “partial”
dipole: molecule with 2 poles
(partial – end and partial + end)
Which of these bonds is the most polar?
greatest
H-Cl H-F O-H C-N
diff. EN
F is a 4.0 (most EN element)
Electronegativity Differences (& Bond Types)
C–H is a NONpolar bond
(2.5 – 2.1 = 0.4)
Bonding Summary
Ionic
(e– transferred)
Polar Covalent
(e– unequally shared)
(ΔEN)
Nonpolar Covalent
(e– equally shared)
SHAPE
polar molecule:
•has polar bonds matters
•arranged asymmetrically
(unbalanced pull in
different directions)
(polar bonds do not cancel out)
net dipole
nonpolar molecule:
•has no polar bonds, or…
•has polar bonds…
arranged symmetrically
(balanced pull in
every direction)
(polar bonds do cancel out)
Cl
Cl
Quick Quiz!
1. In a nonpolar covalent bond, electrons are
A. gained by one atom.
B. shared unequally between atoms.
C. shared equally between atoms.
D. lost by both atoms.
Give 2 example of nonpolar molecules:
Br2, CO2, CCl4
Quick Quiz.
2. In a molecule, the most electronegative atom
A. repels electrons more strongly and
acquires a partial negative charge.
B. repels electrons more strongly and
acquires a partial positive charge.
C. attracts electrons more strongly and
acquires a partial positive charge.
+

D. attracts electrons more strongly and
acquires a partial negative charge.

Quick Quiz.
3. Which of the following bonds is the most polar?
A. H-N
B. O-N
C. H-F
D. Cl-Cl
greatest difference in EN
Quick Quiz.
4. Why is carbon tetrachloride, CCl4,a
nonpolar molecule even though it contains
4 polar C–Cl bonds?
A. The polar bonds are too weak.
B. The polar bonds cancel in opposite
directions.
C. Carbon is always nonpolar.
D. Carbon tetrachloride has single bonds.
Quick Quiz.
5. Which of the following is a polar molecule?
A. H2S
B. CO2
C. NH3
D. I2
S
Cl
Cl
Polar?
or
Nonpolar?
AB4
AB2
AB3
AB4
AB3E
AB2E2