Bonding Class #4
OB: become masterful with both the Double
and the Triple Covalent Bonds, plus some practice
drawing structural diagrams for larger molecules
O2 Oxygen How does it bond? (review)
O
O
Each oxygen needs to gain
2 electrons to fill it’s valence
orbital. Each oxygen must lend
2 electrons to the other.
O
O
Will become…
O O
Drawn structurally… this way:
O=O
Each O has a 3.4 electronegativity value, so this is a
Double Non-Polar Covalent Bond
Looking at the HONClBrIF twins, in order, let’s figure out the
kinds of bonds that they all have… (draw dots or structural's to think)
H2
O2
N2
Cl2
Br2
I2
F2
Looking at the HONClBrIF twins, in order, let’s figure out the
kinds of bonds that they all have…
H2 Single non-polar covalent H―H
O2 Double non-polar covalent O=O
N2 ???
Cl2 Single non-polar covalent Cl―Cl
Br2 Single non-polar covalent Br―Br
I2 Single non-polar covalent I―I
F2 Single non-polar covalent F―F
Time for
some
Thinking!
N
N
We’ll need two nitrogen
atoms, which both need
to follow the octet rule.
How many electrons do
they need to borrow from
each other?
To do that, we’ll
have to rearrange
the electrons so
that they can
share them with
each other.
N
N
Will shift →
N N
And structurally this will become:
N N
Nitrogen shares 3 pairs of electrons, it makes a
triple nonpolar covalent bond
Covalent bonds are between 2 or more nonmetals, and usually
follow the octet rule.
Covalent bonds can be:
SINGLE, DOUBLE, or TRIPLE
They can also be:
POLAR or NON-POLAR
Let’s draw electron dot diagrams and then STRUCTURAL diagrams for these compounds.
DOTS
C2H6
C2H4
Structural
Let’s draw electron dot diagrams and then STRUCTURAL diagrams for these compounds.
DOTS
C2H6
Structural
H
H
C C
H
C2H4
H
H
H
C C
H
H H
H
H
H
H―C―C―H
H H
H H
C C
H H
Let’s draw electron dot diagrams and then STRUCTURAL diagrams for these
compounds. Name each bond type.
C2H2
C3H8
DOTS
Structural
Let’s draw electron dot diagrams and then STRUCTURAL diagrams for these compounds.
DOTS
Structural
C2H2
H
C C
H
H―C C―H
H-C bond is single polar covalent
C-C bond is triple nonpolar covalent
C3H8
H
H
H
C C C
H
H
H H H
H
H
H
H-C bond is single polar covalent
C-C bond is single nonpolar covalent
H―C―C―C―H
H H H
13
Let’s draw electron dot diagrams and then STRUCTURAL diagrams for these compounds.
Name each bond type.
DOTS
CO2
AsCl3
Structural
DOTS
Structural
CO2
O C O
O = C bond is a double polar covalent bond
AsCl3
Cl As Cl
Cl
As – Cl bond is a single polar covalent bond
O=C=O
Carbon dioxide is a
STRAIGHT molecule
Cl―As―Cl
Cl
Propane goes camping with some people in blue
tanks, to run the stoves. It’s a repeating type
molecule, a little chain really. The formula is C3H8.
Do the Structural Diagrams now.
Name both kinds of bonds in this molecule
Propane formula is C3H8.
H H H
H―C―C―C―H
H H H
The C―C bond is single nonpolar covalent
and the C―H bond is single polar covalent
Draw Dot diagrams and structural
diagrams for oxygen dibromide.
Name the bonds between bromine + oxygen.
Structurally, this becomes…
O Br
Br
O Br
Br
These bonds are SINGLE POLAR COVALENT bonds.
EN diff of 3.4 - 3.0 = 0.4
Draw structural diagrams for carbon tetrachloride.
Name the bonds between carbon and chlorine.
CCl4 The Electronegativity difference between Cl - C is
3.2 – 2.6 = of C is 0.6, These are all
single polar covalent bonds.
Cl
Cl C Cl
Cl
Cl
Cl―C―Cl
Cl