Electron Dot and Structual Diagrams for Covalent Compounds

1
Electron Dot and Structual Diagrams for Covalent
Compounds
2
Lewis Structures

• Structural Diagrams show the number of bonds in a
  compound.
• Electron Dot Diagrams show the electrons involved
  in the bonds of compounds.

Non-bonding e- or lone pairs
Bonding e- 1 pair of electrons 1 bond
3
Electron Dot Diagrams

• Determine the number of valence e- for an
  element.

4
7e-
8e-
1e-
valence electrons
2e-
3e-
4e-
5e-
6e-
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Electron Dot Diagrams

• Determine the number of valence e- for an
  element.
• H Cl F S O P N C
  Si
• valence e- 1 7 7 6
  6 5 5 4 4

of bonds 1 1 1 2
2 3 3 4 4
When drawing structural diagrams, each element
must have the correct number of bonds.
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Electron Dot Diagrams

• Each bond in the structural formula represents
  two electrons.
• All valence electrons must be used
• Each element must have a full valence orbital
  (8e-) , except H (2e-)
• Try C2H6

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• First, determine the central atom (the one with
  the most bonding electrons)
• Carbon 4 e-
• Hydrogen 1 e-
• So the central atoms will be? C

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Electron Dot Diagrams

• C2H6

.
C
.
.
.
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Electron Dot Diagrams

• C2H6

.
.
.
.
C
C
.
.
.
.
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Electron Dot Diagrams

• C2H6

.
.
.
.
.
.
.
.
C
C
.
.
.
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.
.
All atoms have a full shell
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Electron Dot Diagrams

• C2H6

.
.
.
.
.
.
.
.
C
C
.
.
.
.
.
.
All atoms have a full shell
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Electron Dot Diagrams

• A structural diagram is one that shows each bond
  as a line. Each line represents 2 bonding
  electrons.
• Lone pairs are not shown in a structural diagram
• C2H6

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Electron Dot Diagrams

• HCN

14
Electron Dot Diagrams

• HCN

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Electron Dot Diagrams

• HCN

H
C
N
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Electron Dot Diagrams

• HCN

.
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.
.
C
.
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Electron Dot Diagrams

• HCN

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C
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.
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Electron Dot Diagrams

• HCN

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.
C
.
.
.
.
.
Atoms have full shells All valence electrons
were used
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• CO2

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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• CO2

O C O
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• CO2

.
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C
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.
.
Atoms have full shells All valence electrons
were used
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• CO2

.
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.
C
.
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.
.
.
Atoms have full shells All valence electrons
were used
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• N2

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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• N2

N N
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• N2

.
.
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.
N
.
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.
.
Atoms have full shells All valence electrons
were used
26
Electron Dot Diagrams

• Try drawing the electron dot diagram for
• N2

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.
N
.
.
.
.
.
Atoms have full shells All valence electrons
were used
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• P2O3 (sym)

28
Electron Dot Diagrams

• Try drawing the electron dot diagram for
• P2O3

O P O P O
Hint This molecule is symmetricalwhich means
an O will be in the center.
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• P2O3

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O
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O
O
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Electron Dot Diagrams

• Try drawing the electron dot diagram for
• P2O3

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O
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O
O
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31
Electron Dot Diagrams

• Try drawing the electron dot diagram for
• C4H8 (cyclic)

32
Electron Dot Diagrams

• Try drawing the electron dot diagram for
• C4H8 (cyclic)

H
H
.
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C
C
H
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.
H
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.
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.
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H
C
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C
.
H
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.
H
H
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Electron Dot Diagrams

• Try drawing structural diagrams for the
• following C4H8 (cyclic)

H
H
C
C
H
H
H
C
C
H
H
H