Bonding
Types of Bonds
Electron Dot Diagrams
Shapes of Molecules (VSEPR)
Intermolecular Forces
James
In Your Textbook
Types of Bonds: pp. 419-424 and 437-446 and 462
Electron Dot Diagrams: pp. 441
Shapes of Molecules (VSEPR): pp. 455-456
Intermolecular Forces: pp. 463-466
Types of Bonds
Covalent
Definition
Example
Electronegativity
Difference
Conductivity
Melting/Boiling
Points
Solubility in
Water
Assignment 1: Types of Bonds
Ionic
Determine the type of bonding between each pair of elements. If bonds formed are ionic,
draw an electron dot diagram. If the bonds are covalent, determine if they are pure or
polar. If polar, show the direction of the polarity.
Cl and Br (3.16 – 2.96 = 0.20)
Li and Cl (3.16 -0.98 = 2.18)
Pure covalent
Ionic
+1
Li
(Lithium chloride)
. . -1
: Cl :
..
H and Cl (3.16 – 2.2 = 0.96)
Al and O (3.44 – 1.61 = 1.83)
Polar covalent
Ionic (Aluminum oxide)

H – Cl
+3
Al
+3
Al
+3
Al
. . -2
: O:
..
. . -2
: O:
..
Ca and N (3.04 – 1.00 = 2.04)
Li and O (3.44 – 0.98 = 1.83)
Ionic (Calcium nitride)
Ionic ( Lithium oxide)
+2
Ca
. . -3
:N:
..
+2
. . -3
Ca
:N:
..
. . -3
:N:
..
+1
Li
Cl and Cl (3.16 – 3.16 = 0)
Sr and Br (2.95 – 0.98 = 2.46)
. . -2
: O:
..
+1
Li
Pure covalent
Ionic (Strontium bromide)
+2
Sr
. . -1
: Br :
..
. . -1
: Br :
..
Ca and F (3.98 – 1.00 = 2.98)
Si and O (3.44 – 1.90 = 1.54)
Ionic (calcium fluoride)
+2
. . -1
Sr
: Br :
..
. . -1
: Br :
..
Polar covalent

Si - O
Name the ionic compounds above.
Is potassium nitrate ionic or covalent? Try to draw a dot diagram. 
Ionic
+1
K
..
. . -1
:O:N::O:
..
:O:
..
Assignment 2: Electron Dot Diagrams
Draw the electron dot diagram for the following covalent compounds.
Determine if the bonds are polar and the direction of polarity:
1. hydrosulfuric acid
wants 12
..
has 8
H:S:H
share 4
‘‘
2. carbon tetrachloride
wants 40
..
has 32
: Cl :
share 8
.. .. ..
: Cl : C : Cl :
.. .. ..
: Cl :
..
polar covalent bonds
toward Cl
polar covalent bonds
toward S
3. aluminum bromide (Al wants 6)
wants 30
..
has 24
: Br :
share 6
.. ..
..
: Br : Al : Br :
..
..
4. dicarbon dihydride (ethyne)
wants 20
has 10
H:C:::C:H
share 10
polar covalent bonds
toward C
polar covalent bonds
toward Br
5. oxygen gas
wants 16
..
..
has 12
:O :: O:
share 4
6. sulfur difluoride
want 24
.. .. ..
has 20
: F : S : F :
share 4
.. .. ..
pure covalent bonds
polar covalent bonds
toward F
7. sulfur trioxide
want 32
..
..
8. carbon monoxide
wants 16
has 24
share 8
: O : S :: O :
.. ..
: O :
. .
polar covalent bonds
toward O
9. hydrofluoric acid
wants 10
..
has 8
H : F :
share 2
..
highly polar (essentially ionic)
toward F
has 10
share 6
: C ::: O:
polar covalent bonds
toward O
10. nitrogen trihydride
wants 14
..
has 8
H : N : H
share 6
..
H
polar covalent bonds
toward N
Assignment 3: Types of Bonds
Determine whether each statement below is true or false?
F
1.
All bonds are the same.
F
2.
Chemical bonds form when nuclei of two atoms are attracted to each
other. Nuclei are both positive and would not attract.
T
3.
In a covalent bond, orbitals overlap and a pair of electrons is shared.
F
4.
An oxygen atom could overlap an orbital with one hydrogen atom and
have a stable electron configuration. Oxygen needs 2 electrons, so 2 H
F
5.
All covalent bonds are the same.
T
6.
Electrons shared in a bond will spend more time orbiting the nucleus of
the atom with the higher electronegativity.
T
7.
Electrons shared in a bond between a hydrogen atom and an astatine atom
are shared equally. They have the same electronegativity.
F
8.
Electrons shared in a bond between a boron atom and a nitrogen atom are
shared equally. N has a higher electronegativity (difference =1.0)
T
9.
Electrons are shared unequally in a polar covalent bond.
F
10.
F
11.
T
12.
The more electronegative element in a polar covalent bond will be the
negative dipole of the molecule.
T
13.
In the compound aluminum sulfide, sulfur is the negative dipole.
T
14.
The bond in KCl is ionic.
T/F 15.
T
16.
T
17.
T
18.
Electrons are shared equally in an ionic bond. In an ionic bond, electrons
not shared at all.
The bond between a lithium atom and a fluorine atom will be covalent.
Polar molecules have higher melting points. Higher than pure, lower than
Ionic
In bonds between K and Br, one electron is transferred from a potassium
atom to a bromine atom.
Ionic compounds tend to form crystalline solids.
Elements that form ionic bonds with each other are usually far apart on the
periodic table.
Determine the type of bonding and draw electron dot diagrams for each of the following
compounds. If the compound is polar, show the direction of polarity (negative pole).
phosphorous trichloride polar bonds
carbon dioxide polar bonds
wants 32
has
26
shares 6
wants 24
has
16
shares 8
.. ..
..
: Cl : P : Cl :
.. ..
..
: Cl :
..
..
..
:O::C::O:
(electrons pulled toward each Cl)
(electrons pulled toward each O)
carbon tetrabromide
calcium oxide ionic bonds
wants 40
has
32
shares 8
..
: Br
..
polar bonds
..
: Br :
..
: C :
..
: Br :
..
+2
Ca
. . -2
: O :
..
..
Br :
..
(electrons pulled toward each Br)
calcium chloride ionic bonds
+2
Ca
. . -1
: Cl :
..
ethyne (C2H2) slightly polar bonds
wants 20
has
10
shares 10
. . -1
: Cl :
..
H: C ::: C :H
(electrons pulled toward C a little)
sulfur dichloride polar bonds
wants 24
has
20
sodium oxide ionic bonds
+1
..
..
..
Na
..
-2
shares 4
: Cl : S : Cl :
..
.. ..
+1
: O :
..
Na
(electrons pulled toward each Cl)
selenium dihydride polar bonds
oxygen dichloride polar bonds
wants 12
has
8
shares 4
wants 24
has
20
shares 4
..
H : Se : H
..
(slight)
..
..
..
: Cl : O : Cl :
..
..
..
(electrons pulled toward Se)
(electrons pulled toward O)
Ethane (C2H6) slightly polar bonds
potassium chloride ionic bonds
wants 28
has
14
shares 14
H
H
..
..
H:C : C :H
..
..
H
H
+1
K
. . -1
: Cl :
..
(electrons pulled toward C a little)
Assignment 4: Predicting Shapes of Molecules
Compound
H2 O
Electron Dot
Diagram
..
H : O : H
..
want 12
has
8
shares 4
Electron
Pairs
Lone
Pairs
Shape
4
2
angular
2
0
linear
3
0
Trigonal
planar
H : Be : H
BeH2
BF3
wants 8
has
4
shares 4
..
..
: F : B : F :
..
..
..
:F:
..
want 30
has 24
share 6
want 40
have 32
share 8
4
0
tetrahedral
SiCl4
..
: Cl :
..
.. ..
: Cl : C : Cl :
.. ..
..
: Cl :
..
want 24
have 20
share 4
4
2
Angular
OCl2
.. ..
..
: Cl : O : Cl :
.. ..
..
Compound
HCl
Electron Dot
Diagram
..
H : Cl :
..
want 10
has
8
shares 2
Electron
Pairs
Lone
Pairs
Shape
n/a
n/a
linear
4
(acts
like 2)
0
linear
want 28
have 20
share 8
4
0
tetrahedral
want 32
have 26
share 6
4
1
pyramidal
4
(acts
like 2)
0
linear
H : C:::N:
HCN
CH2Cl2
PF3
want 18
has 10
shares 8
..
: Cl :
..
H : C : H
..
: Cl :
..
..
:F:
..
.. ..
:F :P : F:
.. ..
..
..
..
: S ::C::S:
CS2
want 24
have 16
share 8
Polarity of compounds on the next page:
H2O
polar bonds and angular shape = polar compound
Oxygen is the negative pole.
BeH2
polar bonds and linear shape (uneven pull is
dispersed) = pure compound
BF3
polar bonds and trigonal planar shape (uneven pull
is dispersed) = pure compound
SiCl4
polar bonds and tetrahedral shape (uneven pull
is dispersed) = pure compound
OCl2
polar bonds and angular shape = polar compound
Oxygen in the negative pole.
HCl
polar bonds and linear shape with Cl pulling the
electrons toward itself = polar compound
Cl is the negative pole.
HCN
polar bonds and linear shape with N pulling
electrons toward itself = polar compound
N is the negative pole.
CH2Cl2
polar bonds and tetrahedral shape (uneven pull
probably dispersed) = pure compound
PF3
polar bonds with pyramidal shape = polar
compound
F end of molecule is the negative pole.
CS2
non polar (pure) bonds, so molecule is pure.
Assignment 5: Molarity problems
Compound
Electron Dot
Diagram
..
..
: I : Al : I :
..
..
..
:I:
..
want 30
has 24
share 6
AlI3
..
:F: S : F:
..
SF2
Al
AlF3
. . -1
:F:
..
. . -1
:F:
..
..
: Cl :
..
..
..
: Cl : C : Cl :
..
: Cl :
..
..
H : Cl :
..
HBr
Lone
Pairs
Shape
3
0
Trigonal
Planar
4
2
Angular
n/a
n/a
Ionic
Forms
Crystals
not
molecules
4
0
Tetrahedral
1/3
0/3
Linear
want 24
has 20
share 4
+3
CCl4
Electron
Pairs
. . -1
:F:
..
want 28
have 20
share 8
want 10
have 8
share 2
Compound
BeF2
Electron Dot
Electron
Diagram
Pairs
..
..
: F : Be : F :
..
..
want 20
2
has 16
share 4
Lone
Pairs
Shape
0
Linear
Pure
..
: O
..
..
: S:: O :
..
:O:
..
want 32
has 24
share 8
3
electron
groups
0
Trigonal
Planar
pure
..
: Cl
..
3
electron
groups
0
CCl2O
..
: C:: O :
..
: Cl :
..
want 32
has 24
share 8
Trigonal
Planar
Slight
polarity
4
1
Pyramidal
Polar
AsCl3
..
..
..
: Cl : As : Cl :
..
..
..
: Cl :
..
want 32
has 26
share 6
4
2
Angular
Polar
SO3
..
H : Se : H
..
SeH2
want 12
has 8
share 4
Assignment 6: Bonding Review
You should be able to:
Describe atomic structure in terms of valence electrons
How do bonds form? (two ways)
How are ions formed specifically?
Describe what type of bond is seen in a compound.
Describe the characteristics seen in compounds with each type of bond. (ex:
would the compound be soluble in water?)
Describe the octet rule as applied to covalent compounds. How many electrons
do atoms want? How many bonds form?
Draw electron dot diagrams for covalent compounds.
Draw structural diagrams for covalent compounds.
Describe the shape of a molecule using VSEPR Theory.
Determine the polarity of a molecule using the electron dot diagram and shape.
Relate the polarity of a molecule of a covalent compound to characteristics seen
by that compound.
Look over all your worksheets and labs for the unit!