REVIEW

Bohr Model Drawings

• Identify the number of Protons, Neutrons, and Electrons in an element. (PEN)

• Write the number of Protons and Neutrons in the center of the nucleus.

• Draw the number of electrons in each of the orbitals.

Energy Levels

Bohr Model Drawings• Carbon

P: E: N:

P:

N:

Valence Electrons and Lewis Dot Diagrams

Groups or Families: Vertical Columns of the Periodic Table

Period or Series: Horizontal Rows of the Periodic table

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 Structures1) Write the element

symbol.

C

Lewis Structures1) Write the element

symbol.2) Carbon is in the 4th

group, so it has 4 valence electrons.C

Lewis Structures1) 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

Electron Cloud

Electron Cloud