Formation of Ionic Bond — Prelims Strategy

Prelims Strategy

To excel in NEET questions on ionic bond formation, a multi-pronged strategy is effective. Firstly, master the definitions of key terms like ionization enthalpy, electron gain enthalpy, and lattice enthalpy, along with their periodic trends.

Understand *why* metals lose electrons and non-metals gain them. Secondly, focus on the energy changes involved: know which steps are endothermic (e.g., ionization, dissociation, sublimation) and which are exothermic (e.

g., first electron gain enthalpy for halogens, lattice enthalpy). Crucially, recognize that lattice enthalpy is the most significant exothermic term, driving the overall stability. Thirdly, memorize the factors favoring ionic bond formation (low IE, high EGE, high lattice enthalpy) and the sub-factors for high lattice enthalpy (high charges, small ionic radii).

For numerical problems involving the Born-Haber cycle, remember Hess's Law and how to sum the enthalpy changes. Practice identifying the correct electron transfer mechanism for various compounds (e.g., $NaCl$, $MgO$, $CaF_2$).

Pay close attention to trap options that might confuse ionic with covalent bonding or misrepresent energy changes.