How to Draw Lewis Structures

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How to Draw Lewis Structures
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Valence Electrons

• Valence electrons are the electrons in the
  highest (outermost) occupied energy level of the
  atom.
• Valence electrons are the only electrons
  generally involved in bond formation.

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Octet Rule

• All atoms, except for Hydrogen and Helium, want 8
  valence electrons in their outer shell to be
  stable.
• This is called the octet rule
• An atom can have a maximum of 8 valence electrons
• Hydrogen an Helium can only have a maximum of two
  valence electrons in their outer shells.

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Lewis Dot Structures

• Gilbert Lewis came up with the idea of electron
  dot diagrams, or Lewis Dot structures
• These diagrams represent an atoms number of
  valence electrons
• It also shows us how many paired and unpaired
  valence electrons an atom has
• Lewis Dot structures help us figure out how
  elements bond

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Lewis Structures

1. Find your element on the periodic table.
2. Determine the number of valence electrons.
3. This is how many electrons you will draw.

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Lewis Structures

• Find out which group (column) your element is in.
• This will tell you the number of valence
  electrons your element has.
• You will only draw the valence electrons.

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Groups - Review
Group 8 8 electrons
Group 1 1 electron
Except for He, it has 2 electrons
Group 2 2 electrons

• Each column is called a group

3, 4, 5, 6, 7

• Each element in a group has the same number of
  electrons in their outer orbital, also known as
  shells.

• The electrons in the outer shell are called
  valence electrons

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Lewis Structures

1. Write the element symbol.
2. Carbon is in the 4th group, so it has 4 valence
   electrons.
3. Starting at the right, draw 4 electrons, or dots,
   clockwise around the element symbol.

C
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Lewis Structures

1. Check your work.
2. Using your periodic table, check that Carbon is
   in the 4th group.
3. You should have 4 total electrons, or dots, drawn
   in for Carbon.

C
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

C
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

H
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

P
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

Ca
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

Ar
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

Cl
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Lewis Structures

• On your worksheet, try these elements on your
  own
• H
• P
• Ca
• Ar
• Cl
• Al

Al
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Elements in the same group have the same Lewis
Dot Structure
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Electron Dot Structure or Lewis Dot Diagram

• A notation showing the valence electrons
  surrounding the atomic symbol.

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End of Study Guide.

• Complete the Lewis Structure Worksheet
• You should know how to draw Lewis Structures for
  the first 54 elements (except the transition
  metals).