Lewis Dot Diagrams
• Each row of the periodic table is called a period
•
All elements in a period have
the same number of
atomic orbitals (or shells)
• Each column of the periodic table is called a group or
family
• All elements in a group
have the same number of
valence electrons
Bohr Diagram Review
• Draw the Bohr diagram for the following:
Oxygen, Fluorine, Sodium
Lewis Dot Diagrams
•Method of representing atoms
•Discovered by Gilbert N. Lewis
•In a dot diagram, only the symbol for the element and the
electrons in its outermost energy level (valence electrons) are
shown
• Eg: Sodium has 1 valence e- in it’s outermost shell, the
diagram for sodium would look like this
Na
Drawing Lewis Dot diagrams in 3 easy steps
Getting Started:
1. Find your element on the periodic table.
2. Determine the number of valence electrons.
-this will be determined by which group your element is in
(eg: Li is in group 1, so it has 1 valence electrons)
3. This is how many electrons you will draw.
• Lone pair – electrons in atom’s valence shell (not used in
bonding)
ex:
Na
• Bonding pair – electron pair involved in bonding
ex:
N
Example 1
- Carbon
1. Write the symbol for the element.
2. How many valence electrons does it have?
3. Start on the top and draw the electrons clockwise or counterclockwise around the element .
4. Check your work— did you draw the correct number of
electrons?
C
Example 2
- Chlorine
Cl
Your Turn
• Draw Lewis diagrams for the following:
Magnesium, Neon and Boron
Mg
Ne
B