Group 18 Elements (Noble Gases) MCQ - Practice Questions with Answers

Electronic Configuration :-All noble gases have general electronic configuration ns np except helium which has 1s 2 . Many of the properties of noble gases including their inactive nature are ascribed to their closed shell structures.

Ionisation Enthalpy :- Due to stable electronic configuration these gases exhibit very high ionisation enthalpy. However, it decreases down the group with increase in atomic size.

Atomic Radii :- Atomic radii increase down the group with increase in atomic number.

Electron Gain Enthalpy :- Since noble gases have stable electronic configurations, they have no tendency to accept the electron and therefore, have large positive values of electron gain enthalpy.

Solubility :- Noble gases are slightly soluble in water and their solubility increases down the group from He to Rn with increase in atomic size.

Electrical conductivity :- These gases have fairly high electrical conductivity.They produce characteristic coloured lights when an electrical discharge is passed through them at low pressure.

In general, noble gases are least reactive. Their inertness to chemical reactivity is attributed to the following reasons:

(i) The noble gases except helium (1s² ) have completely filled ns² ,np⁶ electronic configuration in their valence shell.

(ii) They have high ionisation enthalpy and more positive electron gain enthalpy.

Xe and Kr show some chemical activity at certain conditions.

Reaction with fluorides :-Xe react with fluorides and make different fluorides at different condition.

Oxides:- Xenon fluorides compound react with water and give oxides of xenon.

Oxyfluorides:-