1. Chemical Bonding
Covalent Bonding

2. A. Types of Bonds IONIC COVALENT
Bond Formation
e- are transferred from metal to nonmetal
e- are shared between two nonmetals
Type of Structure
crystal lattice
true molecules
Physical
State
solid
liquid or gas
Melting
Point
high
low
Solubility in
Water
yes
usually not
Electrical Conductivity
yes (solution or liquid) no
Other
Properties
odorous

3. A. Types of Bonds METALLIC e- are delocalized among metal atoms
Bond Formation
e- are delocalized among metal atoms
Type of Structure
“electron sea”
Physical
State
solid
Melting
Point
very high
Solubility in
Water no
yes (any form)
Electrical Conductivity
Other
Properties
malleable, ductile, lustrous

4. Covalent Bonding - True Molecules
A. Types of Bonds
Covalent Bonding - True Molecules
Diatomic Molecule
RETURN

5. B. Bond Polarity
Most bonds are a blend of ionic and covalent characteristics.
Difference in electronegativity determines bond type.

6. B. Bond Polarity Electronegativity
Attraction an atom has for a shared pair of electrons.
higher e-neg atom  -
lower e-neg atom +

7. B. Bond Polarity Electronegativity Trend
Increases up and to the right.

8. B. Bond Polarity Nonpolar Covalent Bond e- are shared equally
symmetrical e- density
usually identical atoms
Electronegativity difference range
0.00 – 0.4

9. + - B. Bond Polarity Polar Covalent Bond e- are shared unequally
asymmetrical e- density
results in partial charges (dipole)
Electronegativity difference range
0.4 – 2.0 + -

10. B. Bond Polarity - + Nonpolar Covalent - no charges
Polar Covalent - partial charges + -

11. B. Bond Polarity
Nonpolar
Polar
Ionic
View Bonding Animations.

12. B. Bond Polarity Examples: Cl2 HCl 3.0-3.0=0.0 Nonpolar 3.0-2.1=0.9
NaCl
=0.0
Nonpolar
=0.9
Polar
=2.1
Ionic

13. Determining Type, DEN
0.3
1.7 5%
50%

14. Determining Type, DEN
Ionic, Polar or Nonpolar Covalent Compounds: The difference in electronegativity between bonding atoms leads to the type of compound.
Example:
O2 , O=O ENO = D EN = 0 g
NO , N=O ENN = 3.0, ENO = D EN = g
CO , C= O ENC = 2.5, ENO = 3.5 D EN = g
NaCl , Na+Cl- ENNa = 0.9, ENCl = D EN = g
Nonpolar Covalent
Polar Covalent
Polar Covalent
Ionic

15. Sample Problem
Use electronegativity differences to classify bonding between sulfur, S, and the following elements: hydrogen, H; cesium, Cs; and chlorine, Cl. In each pair, which atom will be more negative?
Bonding between sulfur and
Electronegativity difference
More-negative atom
Bond type
hydrogen
2.5 – 2.1 = 0.4
Polar-covalent
sulfur
cesium
2.5 – 0.7 = 1.8
Ionic
sulfur
chlorine
3.0 – 2.5 = 0.5
Polar-covalent
chlorine

16. Additional Sample Problems
Complete the following chart:
Elements bonded
Electronegativity difference
More-negative atom
Bond type
a. C and H
2.5 – 2.1 = 0.4
Polar-covalent
carbon
b. C and S
2.5 – 2.5 = 0
Nonpolar covalent
Same electronegativity
c. O and H
3.5 – 2.1 = 1.4
Polar-covalent
oxygen
d. Na and Cl
3.0 – 0.9 = 2.1
Ionic
chlorine
e. Cs and S
2.5 – 0.7 = 1.8
Ionic
sulfur

17. LecturePLUS Timberlake
Learning Check
Identify the type of bond between the following atoms
A. K-N
1) nonpolar ) polar 3) ionic
B. N-O
1) nonpolar 2) polar 3) ionic
C. Cl-Cl
1) nonpolar 2) polar 3) ionic
LecturePLUS Timberlake

18. LecturePLUS Timberlake
Solution
A. K-N 3) ionic
B. N-O 2) polar
C. Cl-Cl 1) nonpolar
LecturePLUS Timberlake

19. Covalent Bonds can have multiple bonds, so you should be familiar with the following…
Single Covalent Bond- chemical bond resulting from sharing of an electron pair between two atoms.
Double Covalent Bond- chemical bond resulting from sharing of two electron pairs between two atoms.
Triple Covalent Bond -chemical bond resulting from sharing of three electron pairs between two atoms.

20. C. Molecular Nomenclature
Prefix System (binary compounds)
1. Less e-neg atom comes first.
2. Add prefixes to indicate # of atoms. Omit mono- prefix on first element.
3. Change the ending of the second element to -ide.

21. C. Molecular Nomenclature
PREFIX
mono-
di-
tri-
tetra-
penta-
hexa-
hepta-
octa-
nona-
deca-
NUMBER 1 2 3 4 5 6 7 8 9 10

22. C. Molecular Nomenclature
CCl4
N2O
SF6
carbon tetrachloride
dinitrogen monoxide
sulfur hexafluoride

23. C. Molecular Nomenclature
arsenic trichloride
dinitrogen pentoxide
tetraphosphorus decoxide
AsCl3
N2O5
P4O10