Module 2 Intro

Module 2—Chemical Compounds

In This Module

Lesson 1—Bonding Theory and Lewis Formulas

In this lesson you will learn to use electron dot diagrams to represent the arrangement of electrons within an atom and to illustrate how atoms bond together. This lesson will also use the periodic table and Lewis symbols to support and explain ionic bonding theory.

• What models are used to describe the bonding between atoms in molecular compounds?
  
  

• Can information contained within the periodic table be used to support and explain bonding theories?

Lesson 2—Molecular Shapes and VSEPR Theory

In this lesson you will study the Valence Shell Electron Pair Repulsion (VSEPR) model, recognized as the defining theory for predicting molecular shapes. The molecular shapes you will examine in this lesson are linear, bent, tetrahedral, trigonal pyramidal, and trigonal planar. An introduction to chemical representations of molecules that demonstrate three-dimensional shape will also be included.

• What is VSEPR theory, and how can it be used to predict molecular shapes?
  
  

• Can the structure of simple molecular substances be illustrated by drawing or building models?
  
  

• How are models and theories useful in helping to explain the structure and behaviour of matter?

Lesson 3—Molecular Polarity

In this lesson you will learn how to determine the polarity of a molecule by analyzing the structural shape and charge distribution within a molecule. Electronegativity, shape, and symmetry all affect the polarity of a molecule. The difference between polar and nonpolar bonds and polar and nonpolar molecules is important in many industrial processes.

• How can you determine the polarity of a molecule by using simple structural shapes and charge distribution?

Lesson 4—Intermolecular Forces

This lesson focuses on the different types of intermolecular bonding that occur within molecules. Intermolecular bonding includes London forces, dipole-dipole forces, and hydrogen bonding. Intermolecular bonding plays a large role in determining many characteristics of molecular substances, including melting and boiling points, solubility, surface tension, cohesion and adhesion, volatility, and density.

• What are intermolecular forces?

  
  

• Are the differences between the melting and boiling points of similar substances explained by differences in their intermolecular forces?
  
  

• How does scientific knowledge and theory develop through hypothesis, evidence collection, investigation, and explanation?

Module Assessment

The assessment for this module consists of four lesson assignments. As you complete these assignments, you will consider some of the larger questions regarding the application of principles of bonding to technologies used throughout history. Your work on these assignments will prepare you to complete the Unit Assessment.