electron dot and structual diagrams for covalent compounds
TRANSCRIPT
Lewis Structures
• Structural Diagrams show the number of bonds in a compound.
• Electron Dot Diagrams show the electrons involved in the bonds of compounds.
H:
H
:O:
:
H-
H-O
Non-bonding e- or lone pairs
Bonding e-
1 pair of electrons = 1 bond
Electron Dot DiagramsDetermine 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
Cl
:
. :: H
.
F
:
. :: : S:
. . : O
:. . . P
:
. . . N
:
. . . C
.
. . .Si
.
. .
# of bonds 1 1 1 2 2 3 3 4 4
When drawing structural diagrams, each element must have the correct number of bonds.
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
Electron Dot Diagrams
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
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
Electron Dot Diagrams
C
H
H
H
H
C
H
H
HCN
C. H N
. .. . . ... .Atoms have full shells
All valence electrons were used
Electron Dot Diagrams
CH N
Try drawing the electron dot diagram for:
CO2
C
.
O
. . ... . O.. . ... .. .
Electron Dot Diagrams
Atoms have full shells
All valence electrons were used
Try drawing the electron dot diagram for:
CO2
C
.
O
. . ... . O.. . ... .. .
Electron Dot Diagrams
C OO
Atoms have full shells
All valence electrons were used
N
.
N.. . . ... ..
Electron Dot DiagramsTry drawing the electron dot diagram for:
N2
Atoms have full shells
All valence electrons were used
N
.
N.. . . ... ..
Electron Dot Diagrams
N N
Try drawing the electron dot diagram for:
N2
Atoms have full shells
All valence electrons were used
Try drawing the electron dot diagram for:
P2O3
Electron Dot Diagrams
O P O P O
Hint: This molecule is symmetrical…which means an O will be in the center.
Try drawing the electron dot diagram for:
P2O3
O
.
P P
. . .. ....O O... . . .. .
. .. .
. ...
. . .
Electron Dot Diagrams
Try drawing the electron dot diagram for:
P2O3
O
.
P P
. . .. ....O O... . . .. .
. .. .
. ...
. . .
Electron Dot Diagrams
PO O OP
Try drawing the electron dot diagram for:
C4H8 (cyclic)
.
C C
CCH
H H
H
H
HH
H.
..
. ..
.
.. ..
.. .
...
.. .
...
Electron Dot Diagrams