Formation of Ionic Bond — Predicted 2026

AI-Predicted Question Angles for UPSC 2026

Based on trend analysis, current affairs, and recurring themes in Formation of Ionic Bond.

Comparative analysis of lattice enthalpies for compounds with varying charges and sizes.

high

NEET frequently tests the application of principles rather than rote memorization. Questions comparing lattice enthalpies of compounds like $LiF$, $NaCl$, $MgO$, $Al_2O_3$ are excellent discriminators. Students need to understand that charge ($q_1q_2$) has a more significant impact than ionic radii ($r$) on lattice enthalpy. A question might ask to rank compounds by increasing/decreasing lattice enthalpy, requiring careful consideration of both factors.

Application of Born-Haber cycle to calculate an unknown enthalpy term.

medium

While direct complex calculations are less common, a simplified Born-Haber cycle problem where one term (e.g., lattice enthalpy or enthalpy of formation) is unknown and others are given, could be asked. This tests the understanding of Hess's Law and the interrelation of various energy terms. The question might provide all values and ask for the overall enthalpy of formation, or provide all but one and ask for the missing value.

Conceptual questions on the 'driving force' of ionic bond formation, distinguishing between octet rule and lattice energy.

high

Students often mistakenly believe the octet rule is the sole driving force. NEET could pose a question that requires a deeper understanding that while octet configuration is a goal for individual atoms, the *overall* stability and formation of the ionic compound is primarily driven by the large, exothermic lattice enthalpy. This tests conceptual clarity and avoids common misconceptions.