Write the favourable factors for the formation of ionic bond.

(N/A) The formation of an ionic bond depends on the ease of formation of positive and negative ions from neutral atoms and their subsequent arrangement in a crystal lattice. The favourable factors are:
$1$. Low Ionization Enthalpy: The metal atom should have low ionization enthalpy so that it can easily lose electrons to form a cation $(M \rightarrow M^+ + e^-)$.
$2$. High Electron Gain Enthalpy: The non-metal atom should have high negative electron gain enthalpy so that it can easily gain electrons to form an anion $(X + e^- \rightarrow X^-)$.
$3$. High Lattice Enthalpy: The ions formed should arrange themselves in a crystal lattice such that the energy released (lattice enthalpy) is high,which stabilizes the ionic compound.