What are the different types of intermolecular forces?

The different types of intermolecular forces (IMFs) are:

1. London Dispersion Forces (Van der Waals forces)
   • Weakest type of force.
   • Present in all molecules (polar and non-polar).
   • Caused by temporary (instantaneous) shifts in electron clouds that create temporary dipoles.
   • Strength increases with larger molecules and more electrons.
2. Dipole–Dipole Forces
   • Occur between molecules that have a permanent dipole (polar molecules).
   • Positive end of one molecule attracts the negative end of another.
   • Stronger than dispersion forces but weaker than hydrogen bonds.
3. Hydrogen Bonding
   • A special, strong type of dipole–dipole interaction.
   • Happens when hydrogen is covalently bonded to a highly electronegative atom (N, O, or F) and is attracted to a lone pair on another molecule.
   • Responsible for properties of water like high boiling point and surface tension.
4. Ion–Dipole Forces
   • Occur between ions and polar molecules.
   • Important in solutions, e.g., when salt (NaCl) dissolves in water.
   • Stronger than dipole–dipole and hydrogen bonds.

In summary:

• London dispersion → weakest, in all molecules.
• Dipole–dipole → in polar molecules.
• Hydrogen bond → strong dipole force with H–N, H–O, or H–F.
• Ion–dipole → strongest, between ions and polar molecules.