intermolecular intercations

• London forces are created by instantaneous dipoles which create induced dipoles in other surrounding ions attracting them to one and other

  (the positive dipole causes near ions electron clouds to be pulled closer towards them)

  
• London forces attractive force increases with increasing numbers of electrons in the molecule.

  The more electrons there are the greater fluctuation in electron density
• the more points of contact in a molecule the stronger the London forces are
• london forces will always be present in a molecule
• permanent dipole-dipole interactions occur when a permanent dipole attracts another permanent dipole where they aligned and are attracted to each other

  
• due to the random movement of molecules permanent dipoles are not always aligned correctly and can repel each other
• due to permanent dipole forces not always attracting molecules together there interactions are less than london forces
• it's possible for a molecule with permanent dipoles to induce a dipole in another molecule being called a permanent dipole-induced dipole
• London forces are instantaneous dipole-induced dipole interactions
• The hydrogen bond is an intermolecular interaction between a hydrogen atom and a N, O, F, atom due to them being very electronegative
• hydrogen bonding can be both intermolecular and intramolecular but the one we look at is mainly intermolecular
• hydrogen bonding is the strongest out of the three forces
• hydrogen bonds tend to have a 180 degree bond angle
• in longer chain alcohols ( like C10H22O) hydrogen bonds become less effective
• hydrogen bonding is extremely strong in water making it an anomaly and have such a high melting point