[This page is still under construction. Last updated 4/29/2025]
This unit is really the capstone for all of the first semester bonding topics. We will explore intermolecular forces (London Dispersion Forces (Van der Waals), Dipole-Dipole Forces, Hydrogen Bonding, and Ion-Dipole Attractions) by using molecular geometry and our knowledge of periodic trends to predict whether molecules are polar or not. We will also dive into the mathematics involved in calculating how much energy is required or released during a phase change and how intermolecular forces can be used to explain why different molecules require different amounts of energy at different temperatures.
Your textbook is a little vague on these topics, so please use the provided supplemental materials (especially the AP questions) to make your studies more effective.
Standards Checklist for the Intermolecular Forces and Phase Changes Sub-Unit
Valence Shell Electron Pair Repulsion Theory (VSEPR Theory) is based on the idea that negative electrons will repel each other in 3D space. Electron pairs around a central atom will spread out as much as physically possible. Each of the resulting shapes has a name (some of them entertaining and some of them fancy) that you will be expected to predict on the AP exam.
Notes: Molecular Geometry Organizer, Filled Out
Worksheets to do WITH Models in Class:
Molecular Geometry Practice 1, Answers
Molecular Geometry Practice 2, Answers
Worksheets to go with these advanced notes (non-AP topic, but helpful for understanding metallic bonds) are below. Each one will be worth 1% applied to the FRQ final exam after the curve. It's small, but it might be worth it if your grade is borderline.
Predicting the polarity of a molecule is the base skill that leads into all of the other questions in this section. To successfully predict polarity, you must be able to draw Lewis Dot Structures with accuracy. You can find a table of electronegativity values on page 383 of your textbook or by using a periodic table app on a TI calculator.
Notes: Predicting Polarity, Filled Out
Worksheets:
Once you can successfully predict the polarity of a molecule, we can introduce how to classify which intermolecular forces a collection of these molecules will experience. When molecules have more intermolecular forces, it affects how well those molecules stick together and therefore properties like surface tension, vapor pressure, boiling point, etc.
Notes: Intermolecular Forces, Filled Out
Intermolecular Forces Concepts, Filled Out (short for after Molecular Geometry Quiz)
Identifying Intermolecular Forces, Filled Out (short for right before the lab)
Lab Handouts:
These activities are for a grade. Keys only available in person in the classroom.
Notes (possibly for after MG Lab Day 2)
Intro to Ranking the Strengths of IMFs, Filled Out
In this segment, we will cover how to classify bond strength vs. intermolecular attractions, and how to use the varying strengths of these to rank melting or boiling points.
In-class activity: Intermolecular Forces P.O.G.I.L. (taken from Chemistry: A Guided Inquiry by Moog)
Worksheets: Organic Functional Groups and Bonding 1, Answers
In this lesson we will explore distillation, paper chromatography and column chromatography. For the 24-25 and 25-26 school years, this lesson is moved to April to serve as a timely review for the AP exam.
Notes: Separating Mixtures, Filled Out
Labette: Paper Chromatography
Lab AP Question 2017 #4 (for notebook)
Review: Atomic Structure 1993, Answers
Notes: Energy and Phase Changes, Filled Out
Worksheets:
The first rule of all intermolecular forces questions: Do not argue with the overlords. The AP question writers will often provide you with data and ask you to provide a possible explanation for a pattern in this data using what you have learned. Always be redundant and list the intermolecular forces for each molecule in the question. Be overly obvious, and clearly state which molecules have matching types of forces and which molecules have more types of forces and/or stronger forces.