Forces acting between molecules
There are three types of intermolecular forces
Van der Waals-act between al molecules and atoms
Dipole-Dipole forces:act only between certain types of molecules
Hydrogen bonding :acts only between certain types of molecules
Dipole-dipole bonding Temporary dipoles exist in all molecules, but in some molecules there is also a permanent dipole
In some molecules they polarity can cancel out such as in linear molecules.
Van der waals
rise from temporary dipole (uneven distribution of electrons) in one molecule that induces dipole in another molecule .
The more electrons, the stronger the van der Waal’s forces between molecules .
This explains why the boiling point of noble gases increases as the atomic number increases.
The boiling point of hydrocrabons icreases as the chain length increases.