M1L3 Explore: Valence Bond Theory

In this module, you will review chemical bonding and molecular geometry. To learn about this lesson specifically, see the What You Will Learn section on this page.

Module Competencies

A ★ indicates that this page contains content related to that LO.

CC1.1 Determine qualifications for molecular bonding based on geometric shapes

LO1.1.1 Identify different types of geometries

LO1.1.2 Identify dipole moments

★ LO1.1.3 Classify the Valence Bond Theory

LO1.1.4 Classify the Molecular Orbital Theory

Overview

What This Lesson Is About

Review of chemical bonding and Molecular Geometry.

What You Will Learn

We see that electronegativity is an important concept in understanding the properties of molecules. (9.5)
We continue to practice writing Lewis structures for molecules and ions and use formal charges to study the distribution of electrons in these species. (9.6 and 9.7)
We learn further aspects of writing Lewis structures in terms of resonance structures, which are alternate Lewis structures for a molecule. We also see that there are exceptions to the octet rule. (9.8 and 9.9)
The chapter ends with an examination of the strength of covalent bonds, which leads to the use of bond enthalpies to determine the enthalpy of a reaction. (9.10)

What to Read

Overby/Chang: Chemistry, 14th Ed. - Chapter 9

Media

Valence Electron Shell Pair Repulsion

Description:

Time: 9:29 min.

Molecular Geometry and Hybridization of Atomic Orbitals

Description

Time: 2:10 min.

Shape Modification

Description

Time: 2:35 min.

Geometric Shapes

Description

Time: 5:52 min.

Types of Molecular Geometry

Description

Time: 10:30 min.

Dipole Moments

Description

Time: 11:46 min.

Supplemental Resources

An extremely flexible and informative periodic table: Periodic table

Periodic Table: Offline Version

Press the play button and then click on the Real Molecules simulation option.

Let’s explore molecular shape and geometry. Draw the Lewis structure and then select each molecule in the PhET simulation. Be sure to select “Model” at the top of the simulation, then select “Show lone pairs” and “Show bond angles.” Fill in the information for each molecule in the following table (use the “Molecule” drop down tool to select each of the following molecules in the PhET simulation):

Table 1

Lewis Structure Table Example
Lewis Structure	Model Bond Angle	Bonding e^- groups (central atom)	Non-bonding e^- groups (central atom)	Total electron groups (central atom)
CH₄
NH₃
H₂O
BF₃
SO₂
CO₂

For more practice download the following file and use the simulation from above to help guide your inquiry:

It's all in the shape: II discovering the behavior of polar molecules