Explain ionic polarisation.

Ionic Polarisation: It takes account of the fact that while some of the atoms in a molecule contain an excess positive or negative charge that of resulting from the ionic character of the bonds, an electric field will going to shift positive (+ive) ions relative to negative (-ive) ions. It leads to an induced moment of various origins from that induced through electron clouds shifting associate to nuclei. The polarisability of ionic measures the shifting of the ions connected to each other such as the electronic polarisability measures shifting of the electrons relative to the nucleus.