ChemLive
Lesson 3.06
Covalent Bonding
and Lewis Structures
Lesson 3.06 Covalent Bonding and Lewis Structures
• What do you already
know?
• What are you here to
learn?
Have your paper, pencil, calculator, and Periodic Table ready. . .
Objectives
• After completing this lesson, you will be
able to:
• Determine how atoms will covalently bond
together based on location on the periodic
table.
• Draw Lewis structures to model covalently
bonded molecules.
Valence Electrons
• How many valence electrons?
Covalent Bonding
• Nonmetals share electrons to complete an
octet (or duet):
– Oxygen needs 2
for an octet
– Hydrogen need 1
for a duet
Covalent Bonding
• How many bonds are formed?
Multiple Bonds
• If more electrons are needed, multiple pairs
can be shared.
– Oxygen shares two
pairs for a double bond
Multiple Bonds
• Multiple bonds are stronger and shorter:
Review
• Ionic bonds exist as formula units – electrons
are transferred (Na+ or O2-) between a metal
and a nonmetal
• Covalent bonds form molecules – electrons
are shared (NO2) between nonmetals
• Polyatomic ions are groups of covalently
bonded atoms with an ionic charge (CO32-)
Lewis Structures
• Steps
– 1.
– 2.
– 3.
– 4.
– 5.
– 6.
Least electronegative element in the center
Calculate total valence electrons
Write skeleton structure
Complete valence electrons
Compare totals
Distribute electrons
Lewis Structures
• CO2
– 1. C
– 2. 4 + 2(6) = 16
– 3.
– 4.
– 5. 20 – 4 = 16
– 6.
erase 4 around C
move electrons to
form double bonds
Lewis Structures
• HCN
– 1. C
– 2. 1 + 4 + 5 = 10
– 3.
– 4.
– 5. 14 – 4 = 10
– 6.
erase 4 around C
move electrons to
form a triple bond
Lewis Structures
• NH4+
– 1. N
– 2. 5 + 4(1) -1 = 8
– 3.
– 4. done
– 5. 8
Lewis Structures
• H2O
– 1.
– 2.
– 3.
– 4.
– 5.
– 6.
Lewis Structures
• NH3
– 1.
– 2.
– 3.
– 4.
– 5.
– 6.
Lewis Structures
• CH4
– 1.
– 2.
– 3.
– 4.
– 5.
– 6.
Activity
Pre-Lab Research
Virtual Lab
Virtual Lab
Submit
Educator
students
Blackboard students: Virtual Lab or hands-on lab
3.06B Intermolecular Forces
Educator: Submit into 4.12 Blackboard: Do the virtual lab or this one
3.06B Intermolecular Forces
Water
Ammonia
Methane
Carbon Dioxide
3.06B Intermolecular Forces
Submit
Educator: Submit into 4.12. Blackboard: if doing hands-on lab, submit into 3.06