ChemLive Lesson 3.06 Covalent Bonding and Lewis Structures.

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 twopairs 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 (CO3

2-)

Lewis Structures

• Steps– 1. Least electronegative element in the center– 2. Calculate total valence electrons– 3. Write skeleton structure– 4. Complete valence electrons– 5. Compare totals– 6. Distribute electrons

Lewis Structures

• CO2

– 1. C– 2. 4 + 2(6) = 16– 3. – 4. erase 4 around C– 5. 20 – 4 = 16 move electrons to– 6. form double bonds

Lewis Structures

• HCN– 1. C– 2. 1 + 4 + 5 = 10– 3. – 4. erase 4 around C– 5. 14 – 4 = 10 move electrons to– 6. 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

SubmitEducator: Submit into 4.12. Blackboard: if doing hands-on lab, submit into 3.06