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Valence Electrons and Lewis Dot Diagrams
Ms. Khericha and Ms. Rowland
Electron Cloud
Electron Cloud
Energy Levels
Valence electrons
• Valence electrons are the electrons farthest away from the nucleus.
• Every group of elements will have a different number of valence electrons
Why are valence electrons important?
• Valence electrons are key to whether or not an atom bonds with another atom
• The number of valence electrons is the “face” an atom shows to other atoms
• One way to show valence electrons is with electron dot diagrams or Lewis dot diagrams
Lewis dot diagrams
• Lewis dot diagrams include the symbol for the element surrounded by dots. Each dot stands for one valence electron
Nucleus H
HydrogenHydrogen
How to find the # of valence electrons
• 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.
Group 1 = 1 electron
GroupsElements in group 1 will have only 1 valence electron
Group 2 = 2 electrons
GroupsElements in group 2 will have only 2 valence electron
Groups Elements in group 3 will have only 3 valence electronGroup 3 = 3 electrons
GroupsGroup 4 = 4 electrons
Elements in group 4 will have only 4 valence electron
Groups Elements in group 5 will have only 5 valence electronGroup 5 = 5 electrons
Group 6= 6 electrons
Groups Elements in group 6 will have only 6 valence electron
Group 7 = 7 electrons
Groups Elements in group 7 will have only 7 valence electron
Group 8 = 8 electronsExcept for He, it has 2 electrons
Groups Elements in group 8 will have only 8 valence electron
Groups - ReviewGroup 1 = 1 electron
Group 2 = 2 electrons
Group 8 = 8 electrons
Except for He, it has 2 electrons
3, 4, 5, 6, 7
How to: 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.4) Draw them starting at the right, and in a
counterclockwise manner.
Lewis Structures
1) Write the element symbol.
C
Lewis Structures
1) Write the element symbol.
2) Carbon is in the 4th group, so it has 4 valence electrons.C
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, counter-clockwise around the element symbol.
C
Practice!
Lewis Structures
H
Lewis Structures
H
Lewis Structures
P
Lewis Structures
P
Lewis Structures
Ca
Lewis Structures
Ca
Lewis Structures
Ar
Lewis Structures
Ar
Lewis Structures
Cl
Lewis Structures
Cl
Lewis Structures
Al
Lewis Structures
Al
Assignment
• You will have the rest of the hour and the weekend to complete the Lewis structures assignment
