1. Intermolecular Forces
Investigating the forces of attraction between molecules, and how they compare to ions and metals

2. Vocab ____________: the forces of attraction between molecules
________: equal but opposite charges separated by a short distance
____________: the intermolecular force in which a hydrogen atom that is bonded to a highly electronegative atom is attracted to an unshared pair of electrons of an electronegative atom in a nearby molecule
_____________: The intermolecular attraction resulting from the constant motion of electrons and the creation of instantaneous dipoles
Intermolecular forces. Dipole. Hydrogen bonding. London dispersion forces.

3. Boiling
To understand the relative strength of intermolecular forces we must first understand how a ______ changes to a _____
If you increase the _________ of a liquid it will reach a point where it begins to boil
The temperature of a substance is really just a measure of how ________ particles are moving
Liquid. Gas. Temperature. Fast.

4. Boiling Continued
In a liquid the particles are moving slow enough that their attractions cause them to _______ together. But they are still able to ______ past each other.
In a gas the particles are moving so fast that the attractions between ________ is no longer able to cause them to stick together
This means boiling is the point where the particles are moving so fast they can overcome the _________ holding them close together in liquids
Watch it in action
Clump. Flow. Particles. Attraction.

5. Relative Strength
The _____ is a good measure of the force of attraction between particles.
IMF vary in strength, but are generally ______ than the bonds joining atoms in molecule, ions in compounds, or metal atoms in solid metals
Section 6.5: Intermolecular Forces
Boiling point. Weaker.

6. Intermolecular Forces
In this section we will focus only on the attractive forces between separate _________
There are a variety of intermolecular forces, and each of them varies in _________
Molecules. Strength.

7. Dipole-Dipole Forces The ________ IMF exist between polar molecules
Polar molecules act as _______ because of their uneven charge distribution
The direction of a dipole is from the _____ pole to the _____ pole. Used a crossed arrow to indicate a dipole.
Strongest. Dipoles. Positive. Negative.

8. Dipoles Continued
The negative region in one polar molecule attracts the _______ region in an adjacent polar molecule
The forces of attraction between polar molecules are known as ______-______ forces
Effect can be seen by comparing boiling points of polar and __________ molecules

9. Molecular Polarity
The polarity of molecules with more than one bond depends on not just polarity of individual bonds, but also on __________ of each bond
This means we must always consider _________ when determining molecular polarity

10. Molecular Polarity Examples

11. Hydrogen Bonding
Some hydrogen containing compounds have unusually ____ boiling points (HF, H2O, NH3)
This is caused by a strong type of dipole-dipole force called _________________
Only compounds made from ____, _____, and _____ with H can make hydrogen bonds
High. Hydrogen bonding. Fluorine, oxygen, and nitrogen.

12. Hydrogen Bonding Continued
Hydrogen bonds form when the electronegative atoms form a highly _______ bond with H
The small and positively charged H atom forms a very strong attraction with _________ electrons on an adjacent molecule
Polar. A lone pair of

13. Strength Comparison of Hydrogen Bonding
Boiling point of phosphine (PH3)_______
Boiling point of ammonia (NH3)________
BP H2S ________
BP H2O ________

14. Induced Dipoles
A polar molecule can _______ a dipole in a nonpolar molecule by temporarily attracting its _________
This creates a temporary dipole with the side nearest the attracted electrons becoming partially _________ charged
This is a _______ attraction than dipole-dipole attractions
Induce. Electrons. Negatively. Weaker.

15. London Dispersion Forces
The random movement of electrons creates uneven distribution of _________
At any moment there could be a short-lived and weak ______ created
These are the only forces between _______ gas atoms and ___________ molecules
The ________ of all attractive forces
Electrons. Dipole. Noble. Nonpolar. Weakest.