. Group (Inert gases) elements: . . Occurrence: All the noble gases occur in the atmosphere.
Physical properties: As we move along the noble gas elements, their atomic radius and boiling point increases from helium to radon. The first ionization energy decreases from helium to radon. Noble gases have the largest ionisation energy compared to any other elements in a given row as they have completely filled orbital in their outer most shell. They are extremely stable and have a small tendency to gain or lose electrons.
The common physical properties of the group elements are listed in the Table. Property Neon Argon Krypton Xenon Radon Physical state at K Gas Gas Gas Gas Gas Atomic Number XII XII - - - - Isotopes Ne Ar Kr Xe Rn, Rn, Rn Atomic Mass (g.mol - at K) . . .
. [ ] Electronic config- uration [He]2s 2p [Ne]3s 3p [Ar]3d 4s 4p [Kr]4d 5s 5p [ Xe ] 4f 5d 6s 6p Atomic radius (Å) . . .
. . Density (g.cm - at K) . x - .
x - . x - . x - . x - Melting point (K) .
. . . Boiling point (K) .
Table . Physical properties of group elements Properties of inert gases: Physical properties: Noble gases are monoatomic, odourless, colourless, tasteless, and non-inflammable. They are highly unreactive. They are non-metallic in nature.
Chemical Properties: Only the xenon and krypton show some chemical reactivity. Xenon fluorides are prepared by direct reaction of xenon and fluorine under different conditions as shown below. Xe + F XeF Xe + 2F XeF X Ni C Ni /acetone C → → e + 3F XeF Ni / atm C → When XeF is heated at °C in a sealed quartz vessel