Group 18 Elements — Prelims Strategy

Prelims Strategy

To excel in NEET questions on Group 18 elements, a multi-pronged strategy is essential. Firstly, master the electronic configuration of all noble gases and understand how it dictates their general inertness, high ionization enthalpy, and positive electron gain enthalpy.

For numerical or comparative questions, focus on the trends down the group: atomic size, boiling points, and density increase, while ionization enthalpy decreases. Memorize the specific uses of each noble gas, as these are common factual questions.

For Xenon compounds, which are a high-yield sub-topic, practice determining hybridization and molecular geometry using VSEPR theory. This involves calculating the steric number (sum of bond pairs and lone pairs) accurately.

Remember the common structures: XeF$_2$ (linear, $sp^3d$), XeF$_4$ (square planar, $sp^3d^2$), XeF$_6$ (distorted octahedral, $sp^3d^3$), XeO$_3$ (pyramidal, $sp^3$), and XeOF$_4$ (square pyramidal, $sp^3d^2$).

Be mindful of trap options that might reverse trends or misattribute properties or uses to the wrong noble gas. Always read the question carefully, especially when it asks for 'incorrect' statements. Practice hydrolysis reactions of Xenon fluorides, noting the different products for partial vs.

complete hydrolysis.