Title: Lewis Electron Dot Structure
1Lewis Electron Dot Structure
2(No Transcript)
3Lewis electron dot structures
- Dots are placed around a symbol to indicate the
number of valence e- - Valence electrons are the outer shell electrons.
4Arranging the dots
2
6
X
3
5
1
7
4
8
- Dots can be rearranged to
- accommodate bonding illustration.
5Note that the arrangement of dots is the same
within each group.
6The Octet Rule
Octet Rule Atoms share, loose or gain electrons
when they react to have 8 electrons in their
outer shell. Hydrogen will only have 2
electrons. Helium only has 2 electrons Note
There are exceptions to the octet rule.
7Arranging the dots for an atom
H
Cl
8Arranging the dots for a molecule
9Arranging the dots and lines for a molecule
Replace bonding pairs with a line, but always
show the lone pairs of electrons.
Notice that each atom is obeying its proper
rule upon completion of the dot structure.
10Arranging the dots for water
11Final structure for water
H
O
H
12Arranging the dots forcarbon dioxide
13Arranging the dots forcarbon dioxide
14Arranging the dots forcarbon dioxide
C
O
O
15Final structure forcarbon dioxide
C
O
O
16Arranging the dots forcarbon monoxide
17Arranging the dots forcarbon monoxide
O
18Arranging the dots forcarbon monoxide
O
C
How many electrons does the oxygen have around
it?...the carbon?
Since O has 8 electrons, and C has four,
move electrons around to satisfy the octet rule.
19Arranging the dots forcarbon monoxide
O
C
20Final structure forcarbon monoxide
O
C
21Polyatomic ions OH1-
H
O
22OH1-
- Add brackets around the ion.
1-
H
O
Place the charge of the ion outside of the
brackets.
23OH1-
- So, where did the extra electron originate?
1-
H
O
Maybe a sodium atom was strolling byand donated
an electron to the cause.
24CO32-
- Carbon is the central atomit only appears one
time.
C
Place four bonds around the central atom as
indicated by the Kelter Method, but you only have
3 perimeter atoms
25CO32-
O
O
C
O
Make each O atom have 8 e-. Two O atoms
already have 2 e- and one O atom has 4 e- 6 dots
need to be added to two O atoms and 4 dots need
to be added to one O atom. Account for all owned
electrons.
26CO32-
2-
- Add brackets around the ion.
Place the charge of the ion outside of the
brackets.
27BI3
- Boron has three valence electrons
- This molecule is an example of an exception to
the octet rule because the central atom will only
have 6 electrons, not 8.
28BI3
- Boron is the central atomthere is no way only
one bond can accommodate 3 Is!
B
Place the number of bonds around the central atom
that will take care of all of the perimeter atoms
29BI3
- Attach the perimeter I atoms.
Make each I atom happy with 8 e-. Each I atom
already has 2 e- 6 dots need to be added to each
I atom
30BeF2
Be
31Now, practice alot