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Bonding - Verrel (Ionic and covalent bonds and structures (Giant ionic…

- - - - Van der Waals forces are weak intermolecular forces due to their variable nature. It can be said however, that longer straight chain molecules will have stronger Van der Waals forces than branched molecules, due to the fact there is a larger surface area in contact with other molecules, spreading the dipole. The more electrons there are, the stronger the force is too.
    - - Hydrogen bonds significantly increase the melting and boiling points of compounds, moving them away from the general trend of an increase as they are abnormally high, requiring larger amounts of energy to break.
    - - Molecules with permanent dipoles tend to have higher boiling points compared to molecules with only temporary ones, however they usually have a small effect, and can sometimes be outweighed by larger molecules with more electrons and no permanent dipoles.
- - - - An ionic bond forms when a metal transfers its electrons to a non metal atom, in order to gain a stable noble gas configuration. They form giant ionic lattices of repeated oppositely charged ions.
        
        Dative covalent bonds, also known as coordinate bonds, are covalent bonds where the shared pair of electrons come from the same atom i.e in NH4+ - the nitrogen donates its lone pair to a H+ ion making it positive.
        
        We know ions exist as a dissolved solution of an ionic compound can carry an electric current across it, whereas the solvent (water) does not do this on its own. This requires the solution to have positive and negative particles that can transfer electrons, and these are what we call ions.
        
        Polarisation in ions refers to how highly charged ions can distort the electron clouds of the other ions. For example, a highly charged cation may pull some electrons from the anion closer to itself. This change results in the molecule having some covalent properties - this is known as intermediate bonding.