Intermolecular Forces Flashcards
What are intermolecular forces?
Interactions between atoms from separate adjacent molecules
What is the difference between intermolecular and intramolecular forces?
- Intermolecular forces exist between DIFFERENT molecules
- Intramolecular forces exist between separate parts of the SAME molecule
- Intermolecular forces are much weaker but are responsible for the physical properties of substances
What are the 3 types of intermolecular attractive forces that exist between neutral molecules?
- Dipole-dipole forces
- London dispersion forces
- Hydrogen bonding
What type of intermolecular force exists between polar molecules?
Ion-dipole force
Where does an ion-dipole force exist?
Between an ion and the partial charge on the end of a polar molecule
How do dipole-dipole forces occur?
When the positive end of one molecule is near the negative end of another
What force is weaker; ion-dipole or dipole-dipole?
Dipole-dipole forces
Where to London dispersion forces occur?
- Between non-polar molecules (polarised electron charge densities)
What is a hydrogen bond?
A special type of intermolecular attraction between the hydrogen atom in a polar bond and an unshared pair of electrons on a nearby small electronegative ion or atom
List the forces from strongest to weakest?
- Hydrogen bonding
- Ion-dipole
- Dipole-dipole
- London dispersion
What is the correlation between boiling points and molecular mass?
Boiling points increase with molecular e mass due to increasing dispersion forces
Where does hydrogen bonding occur?
Between the hydrogen atom in a polarised covalent bond (delta + and delta -) and a lone pair of electrons on a nearby small electronegative ion or atom
