Intermolecular Forces Flashcards
Intermolecular force
Weak force of attraction found between molecules, ions or atoms of the noble gases
Substances formed
Covalent bonding:
- Non- polar molecules
- Polar molecules
Ionic bonding
- ions (cations)
- ions (anions)
Types of intermolecular forces
- Ion- ion forces (ionic bonding)
- Ion - dipole forces (ion- polar molecule)
- Ion - induced dipole force (ion - non-polar molecule)
Der waals:
- Dipole- dipole force (polar molecule - polar molecule)
- Dipole - induced dipole (polar molecule - non polar molecule)
- Induced dipole - induced dipole (London Forces… non polar - non polar)
Ion - ion forces
- strongest intermolecular force
- between cation and anion
- ionic bonding
Ion - dipole forces
The positive ions will attract the S- polar molecule and the negative ions will attract the S+ polar molecule
Ion- induced dipole
A temporary dipole will forge as the positive ion will attract the electrons to move towards it. The negative ion will repel the electrons
Dipole - dipole forces
Between polar molecules, must identify that they are polar molecules.
The S- will attract the S+ and vice versa
Dipole - induced dipole
S+ side will of the dipole will attract the electrons. Making one side S- and the other S+
Induced dipole - induced dipole
- London forces
- weakest intermolecular force
- found between non-polar molecules
Hydrogen bonding
- NH3/H2O/HF
- polar molecules
- very large eneg
- lone pairs of ē
Properties of hydrogen bonding
- stronger than Van Der Waals forces
- act over shorter distances than Van Der Waals forces
- directed (between lone pair and hydrogen)
Properties of Van Der Waals forces
- occurs between all molecules and atoms
- relatively weak forces of attraction
- act over great differences
- acts in all directions
