Ionic Bond - Formation

Formation

A formation of an ionic bond proceeds when the atom of an element (usually metal), whose ionization energy is low, releases some of its electron(s) to achieve a stable electron configuration and after releasing some of its electron(s) the atom becomes a cation. The atom of another element (usually non metal), whose electron affinity is positive, then accepts the electron(s), again to attain a stable electron configuration and after accepting electron(s) the atom becomes an anion. Typically, the stable electron configuration is one of the noble gases for elements in the s-block and the p-block, and particular stable electron configurations for d-block and f-block elements. The electrostatic attraction between these two entities forms the ionic bond.it is formed to attain stable octate structure.

For example, common table salt is sodium chloride. When sodium (Na) and chlorine (Cl) are combined, the sodium atoms each lose an electron, forming cations (Na+), and the chlorine atoms each gain an electron to form anions (Cl−). These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).

Na + Cl → Na+ + Cl− → NaCl

The removal of electrons from the cation is endothermic, raising the system's overall energy. There may also be energy changes associated with breaking of existing bonds or the addition of more than one electron to form anions. However, the action of the anion accepting the cation's valence electrons and the subsequent attraction of the ions to each other releases energy and thus lowers the overall energy of the system.

Ionic bonding will occur only if the overall energy change for the reaction is favorable – when the reaction is exothermic. The larger the resulting energy change, the stronger the bond. The low electronegativity of metals and high electronegativity of non-metals means that the reaction is most favorable between a metal and a non-metal.