Some of the major factors influencing the formation of ionic bond are as follows:
An ionic bond is formed by the complete transference of one or more electrons from the outer energy shell (valency shell) of one atom to the outer energy shell of the other atom. In this way, both the atoms acquire the stable electronic configurations of the nearest noble atom. The atom from which the electrons are transferred i.e., the atom which loses the electrons, acquires a positive charge and becomes cation.
The atom which gains the electrons acquires a negative charge and becomes anion. The electrostatic attraction between the oppositely charged ions results in the formation of an ionic bond or electrovalent bond between the two atoms and the compounds are called ionic compounds or electrovalent compounds, e.g.,
1. Ionization energy:
It is defined as the amount of energy required to remove the most loosely bound electron from an isolated gaseous atom of an element. The lesser the ionization energy, the greater is the ease of the formation of a cation.
2. Electron affinity:
It is defined as the amount of energy released when an electron is added to an isolated gaseous atom of an element. The higher the energy released during this process, the easier will be the formation of an anion.
Thus, low ionization energy of a metal atom and high electron affinity of a non-metal atom facilitate the formation of an ionic bond between them.
3. Lattice energy:
It is defined as the amount of energy released when cations and anions are brought from infinity to their respective equilibrium sites in the crystal lattice to form one mole of the ionic compound. The higher the lattice energy, the greater is the tendency of the formation of an ionic bond. The higher the charges on the ions and smaller the distance between them, the greater is the force of attraction between them.