Write the favourable factors for the formation of ionic bond.

(N/A) The formation of an ionic bond is governed by the following factors:
$1$. Low Ionization Enthalpy: The formation of a cation from a neutral atom $(M_{(g)} \rightarrow M_{(g)}^{+} + e^{-})$ requires energy. Lower ionization enthalpy $(\Delta_{i} H)$ makes it easier to form the cation.
$2$. High Negative Electron Gain Enthalpy: The formation of an anion from a neutral atom $(X_{(g)} + e^{-} \rightarrow X_{(g)}^{-})$ releases energy. $A$ more negative electron gain enthalpy $(\Delta_{eg} H)$ is favorable for the formation of the anion.
$3$. High Lattice Enthalpy: The formation of the crystal lattice from gaseous ions $(M_{(g)}^{+} + X_{(g)}^{-} \rightarrow MX_{(s)})$ releases a large amount of energy. $A$ high negative lattice enthalpy $(\Delta_{L} H)$ stabilizes the ionic compound.
In summary,ionic bonds form most easily between elements with low ionization enthalpies and elements with high negative electron gain enthalpies,leading to a stable crystal lattice structure.