4Attractions Between Molecules - Google Slides

Page 1

Attractions Between Molecules

• Overview of intermolecular forces influencing molecular interactions.

Page 2

Intermolecular Attractions

• Definition: Attractions between 2 separate molecules.

• Characteristics:

  • Weaker than ionic, metallic, or covalent bonds.

  • Plays a crucial role in determining the phase of matter: solid, liquid, or gas.

Page 3

Van der Waals Forces

1. London Dispersion Forces

• Definition: Forces occurring between nonpolar molecules.

• Characteristics:

  • Weakest of all forces of attraction.

  • Caused by the motion of electrons.

  • Strength of the force increases with:

    • The number of electrons.

    • The mass of the atom.

Page 4

Van der Waals Forces

2. Dipole-Dipole Interactions

• Definition: Interactions occurring when polar molecules are attracted to one another.

• Characteristics:

  • Involves oppositely charged regions of molecules.

  • Similar in nature to ionic bonds.

Page 5

Hydrogen Bonding

• Definition: Attracts hydrogen to an unshared electron pair of an electronegative atom.

• Common interactions:

  • Occurs between Hydrogen and:

    • Nitrogen (N)

    • Oxygen (O)

    • Fluorine (F)

• Strength: Strongest of all intermolecular forces.

Page 6

Intermolecular Flowchart

• Overview of molecular attraction mechanisms:

  • Motion of electrons causes instantaneous dipoles.

  • London dispersion forces applicable to nonpolar molecules:

    • Strong enough to form solids or liquids.

  • Electrostatically caused attractions lead to three states of matter:

    • Solid

    • Liquid

    • Gas

  • Weak interactions in gases can be from:

    • Permanent dipoles.

    • Polar molecules.

    • Dipole-dipole forces, resulting from differences in electronegativity.

    • Hydrogen bonds.

Page 7

Properties of Bonding