By the end of this lab, students should be able to:
- Draw the Lewis Dot structures for molecules that obey the octet rule.
- Draw Lewis Dot structures for molecules that don't obey the octet rule.
- Predict the electron geometry and molecular shape of individual molecules using VSEPR theory.
Prior Knowledge and Helpful Links:
Molecular compounds are formed when two non-metals share valence electrons forming a covalent bond. This results in two types of orbitals; bonding orbitals, where the valence electrons are shared between two nuclei, and non-bonding orbitals (lone pairs), where the valence electrons are localized to one nucleus. Molecules have definite geometric shapes which influence their chemical properties and behavior. The first step in understanding a molecule's geometry is in determining the connectivity of the atoms, and the types of orbitals each atom possesses. This can be conveniently done with Lewis dot structures, which account for all valence electrons by using lines between atoms to represent bonding electron pairs and dots to represent lone electrons.
This pre-lab assignment is an individual assignment to be completed on your own with the help of the "Prior Knowledge" links at the top of this page. All work must be in your own words. Do not copy and paste information from the internet. The assignment will be due 10 minutes before your lab begins. Late work will not be accepted.
The document below is a preview only. Please do not try to screenshot or print it off. You will be able to find your assignment to work on in your Google Classroom.
Group Molecular Theory Worksheet
Using Zoom Breakout rooms, you will work collaboratively with your group on a Google Doc worksheet called "Group Molecular Theory Worksheet". Each person can type in this document at the same time. Remember, part of your grade comes from your participation during lab, so there will be a Peer Evaluation this week. Make sure you are contributing to discussion and to the completion of the worksheet. The worksheet will be due by the end of your lab session, and late work is not accepted. Be sure to turn your assignment in on Google Classroom.
Use the PhET simulation (CC-BY-4.0) below to complete the worksheet with your group.
The document below is a preview only. Please do not try to screenshot or print it off. You will be able to find your assignment to work on in your Google Classroom during lab.
Post-Lab Problem Set
After you have had a chance to view the PhET simulation and complete the worksheet with your group during lab, you will be given the Molecular Theory Post-Lab Problem Set. This is an individual assignment that must be completed on your own, and it is based on your Pre-Lab Primer and your In-Lab Assignment. You may use the PhET simulation to help you as well. This assignment will be due the day after your lab meets by 5 p.m. For example, if your lab is on Monday, the Post-Lab Problem Set will be due on Tuesday at 5 p.m. No late work is accepted.
The document below is a preview only. Please do not try to screenshot or print it off. You will be able to find your assignment to work on in your Google Classroom once you have finished your in-lab assignment.
Contributors and Attributions
Robert E. Belford (University of Arkansas Little Rock; Department of Chemistry) led the creation of this page for a 5 week summer course.
Elena Lisitsyna contributed to the creation and implementation of this page, including generation of the HP5 questions.
- Mark Baillie coordinated the modifications of this activity for implementation in a 15 week fall course, with the help of Elena Lisitsyna and Karie Sanford.