hydrogen bonding

• strongest type of intermolecular force
• only form between hydrogen and the 3 most electronegative atoms: nitrogen, oxygen and fluorine
• the lone pair on these atoms forms a bond with a H atom from another molecule, shown with a dotted line
• molecules held together with H bonds have much higher melting and boiling points compared to similar sized molecules without H-bonding
• this shows how the type of intermolecular forces acting between the molecules heavily influences the physical properties of a substance