Module 2 Intro

Module 2—Chemical Compounds

Lesson 2—Molecular Shapes and VSEPR Theory

Get Focused

Summer activities are often disturbed by swarms of bloodthirsty mosquitoes. You may include insect repellent on your equipment list when you go camping or enjoy other outdoor activities. In some parts of the world, mosquitoes spread infectious diseases, such as malaria or the West Nile virus. Recently it was discovered that the West Nile virus has reached Alberta, causing the government to launch a public health campaign to minimize exposure to mosquito bites. One prevention method is to use insect repellent, the most common of which contains DEET.

DEET is used now, but what repellent was used by First Nations people and the early settlers in Alberta? You may have heard about alternative insect repellents, including citronella and carbon dioxide. Are these alternatives, or traditional methods, effective? It might surprise you to find that the effectiveness of insect repellent is partially determined by the shape of molecules like DEET.

Essential Questions

• 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?

Module 2: Lesson 2 Assignment

Save a copy of the Module 2: Lesson 2 Assignment to your course folder. You will receive more instructions about how to complete the assignment later in this lesson.

You must decide what to do with the questions that are not marked by the teacher.

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.