Answer:An ion-dipole force is a force between an ion and a polar molecule. A hydrogen bond is a dipole-dipole force and is an attraction between a slightly positive hydrogen on one molecule and a slightly negative atom on another molecule.
An intermolecular force is a force that holds molecules of a substance together in a particular state of matter. When a molecule is composed of different atoms having a large electro negativity difference, the bonding pair of electrons is attracted to nucleus of one of the bonding atoms more than it is to the nucleus of the less electronegative atom. A permanent dipole thus results in the molecule. This permanent dipole can attract the permanent dipole in another molecule of the same substance leading to strong dipole-dipole interaction.
Only two elements are liquid at standard conditions for temperature and pressure: mercury and bromine. Four more elements have melting points slightly above room temperature: francium, caesium, gallium and rubidium.
