Valence Electrons and Lewis
Dot Structures
ve- = valence electrons
1 ve-
3 ve- 4 ve- 5 ve- 6 ve- 7 ve-
2 ve-
IGNORE THESE YOU WILL USE THEM IN CHEM NOT BIO
118
Known
Elements
8 ve-
Valence Electrons Practice
1. How many valence electrons are in Carbon?
2. How many valence electrons are in Argon?
3. How many valence electrons are in Beryllium
4. How many valence electrons are in Lithium
5. How many valence electrons are in Francinium?
6. How many valence electrons in Calcium?
7. How many valence electrons in Kyrpton?
8. How many valence electrons in Arsenic?
9. How many valence electrons in Magnesium?
10.How many electrons in Oxygen?
Lewis Structures
•All you have to do for a Lewis
Structure is draw Dots around
an Element’s Symbol
•But How Many????
What you are about to learn
1. How many Electrons are
found in any Element’s
Valence Shell
2.How to draw a Lewis
Structure
So…
•The amount of dots you draw
for a Lewis Structure (LS for
short) is equal to the # of
Valence Electrons in an Atom
Valence Electrons
•The # of Valence e- an atom
has is dictated by the Group
the Element is in
•Groups are the Vertical
Columns on the Periodic
Table!!! It’s So Simple!!!!
Practice:
•The First Two Are Tricky so pay
attention
Practice:
•All Elements in the first group
have only 1 Valence e-
Practice:
•All Elements in the first group
would have a LS like this:
H
Practice:
•All Elements in the second
group have only 2 Valence e-
Practice:
•But what about Helium!!!
•It only has 2 e- so it can only
have 2 e- in its Valence Shell
Practice:
•All Elements in the second
group would have a LS like this
He
So…
•Group 3
•3 Valence e•Structure like this:
B
Lewis Dot Structure Order
Now you should know
1. How many Electrons are found in
any Element’s Valence Shell
2. How to draw a Lewis Structure
Element
Calcium
Carbon
Hydrogen
Helium
Oxygen
Fluorine
Neon
Sodium
Aluminum
Group Number (PT)
2
4
1
8
6
7
8
1
3
# of Valance Electrons
2
4
1
2
6
7
8
1
3
Lewis Dot Structure
Ca
C
H
He
O
F
N
Na
Al