3.1 Intermolecular Forces

• Intermolecular forces are much weaker than intramolecular forces.
• Match the feature with the type of force:

  Nature ↔️ Attraction between molecules

  Strength ↔️ Weaker

  Affect ↔️ Physical properties
• Rank the intermolecular forces from weakest to strongest:

  1️⃣ London Dispersion Forces

  2️⃣ Dipole-Dipole Interactions

  3️⃣ Hydrogen Bonding

  4️⃣ Ion-Dipole Forces
• Dipole-Dipole Forces are stronger than Hydrogen Bonding.

  False
• London Dispersion Forces increase with the size of the molecule.


  True
• Hydrogen bonding occurs when hydrogen is bonded to a highly electronegative atom such as oxygen
• Hydrogen bonding is a strong IMF caused by the attraction between hydrogen and electronegative atoms such as fluorine
• Higher molecular weight molecules have stronger London Dispersion Forces due to more electrons available for forming temporary dipoles

  True
• Match each factor with its effect on IMFs:

  Molecular Shape ↔️ Linear shapes increase IMFs

  Molecular Weight ↔️ Higher weight increases LDFs
• The strength of intermolecular forces (IMFs) affects the physical properties of substances.


  True
• An increase in molecular weight generally leads to higher boiling and melting points.


  True
• Dipole-dipole interactions are stronger than hydrogen bonding.

  False
• Stronger IMFs lead to higher boiling points and melting points.


  True
• Substances with similar IMFs are typically more soluble in each other, following the "like dissolves like" principle.
• What are intermolecular forces (IMFs)?

  Forces between molecules
• Ion-dipole forces are the strongest type of intermolecular force.
• London Dispersion Forces occur in all molecules, polar or nonpolar.


  True
• What causes dipole-dipole interactions?

  Polarity of molecules
• Match the intermolecular force with its description:

  London Dispersion Forces ↔️ Weakest, temporary dipoles

  Dipole-Dipole Interactions ↔️ Moderate, polar molecules

  Hydrogen Bonding ↔️ Strong, H bonded to F, O, N
• Intermolecular forces affect physical properties, while intramolecular forces affect chemical properties.
• What type of intermolecular force is the weakest?

  London Dispersion Forces
• Between what type of molecules do dipole-dipole interactions occur?

  Polar molecules
• Match each type of intermolecular force with its explanation:

  London Dispersion Forces ↔️ Temporary dipoles in nonpolar molecules

  Dipole-Dipole Forces ↔️ Attractions between polar molecules

  Hydrogen Bonding ↔️ Attraction between H bonded to F, O, or N and another electronegative atom

  Ion-Dipole Forces ↔️ Attractions between ions and polar molecules
• Linear molecules have stronger IMFs because they can pack closer together, increasing their surface
• Intermolecular forces affect the chemical properties of substances

  False
• Higher molecular weight molecules have stronger London Dispersion Forces (LDFs) due to more available electrons.
• London Dispersion Forces are the weakest type of IMFs and occur in nonpolar molecules.
• Ion-dipole forces are the strongest type of IMFs.
• Which intermolecular force is the weakest?

  London Dispersion Forces
• How do intermolecular forces affect physical properties like boiling points?

  Increase with stronger IMFs
• Dipole-dipole interactions occur between polar molecules.
• London Dispersion Forces arise from temporary dipoles in nonpolar molecules.
• What types of intramolecular forces exist?

  Covalent, Ionic, Metallic
• Match the intermolecular force with its cause:

  London Dispersion Forces ↔️ Temporary dipoles

  Dipole-Dipole Interactions ↔️ Polarity of molecules

  Hydrogen Bonding ↔️ H bonded to F, O, N
• London Dispersion Forces are caused by temporary dipoles in polar molecules

  False
• Are intermolecular forces stronger or weaker than intramolecular forces?

  Weaker
• What are the two primary factors influencing the strength of intermolecular forces?

  Molecular shape and weight
• Why is hydrogen bonding particularly strong?

  High electronegativity
• Hydrogen bonding is a special case of dipole-dipole interaction involving hydrogen bonded to F, O, or N.
• Spherical molecules have weaker IMFs due to their smaller surface areas.


  True