Why are noble gases in general chemically inert?
Noble gases are generally chemically inert because.
(i)                  All these elements have stable ns2 np5 configuration. Helium has 1s2 configuration.
(ii)                They have high ionisation energies and thus have no tendency to lose electrons.
(iii)               They have zero electron affinity due to which they have no tendency to gain electrons.   
Why ease to liquefy noble gases increases with increase in atomic number?
                The ease of liquefaction of a gas depends upon the magnitude of attractive forces in its molecules. The attractive forces in such gases are Vander Waal’s forces and their magnitude increases with increase in atomic size. Since atomic size increases down the group, so the ease of liquefaction increases down the group.
Besides from atmosphere, how is helium obtained?
                Helium can also be obtained from natural gas which contains 2-7% helium. It can also be obtained by heating cleveite which is an ore of uranium.
Why XeF2 is linear in spite of the fact that Xe is sp3 d hybridised?
                The reason is that xe atom has three lone pairs of electrons and after various repulsions, it acquires linear structure.
Which noble gas has the highest boiling point?
                Xe is largest in size and the magnitudes of Vander Waal’s forces in it are maximum.  Hence it has the highest boiling point.
Give reason which prompted Berthelot to prepare first noble gas compound.
                The preparation of first noble gas compound, XePtCl6 was based on the chance discovery of O2PtCl6. Bartlett predicted that Xenon should react with PtCl6 to form the ionic compound because.
(i)                  The ionisation energies of O2 and Xe are comparable
(ii)                The molecular diameter of O2 and Xe are also similar.
He obtained a crystalline compound of composition, XePtCl6 on just mixing Xe and PtCl6 at room temperature.
                        Xe+PtCl6 (g) ž Xe+(PtCl6)-(s).
Which noble gas can be used in botanical gardens?
        Neon lamps are used in botanical gardens and also in green houses. This gas stimulates growth and is also effective in the formation of chlorophyll.
Which inert gas/gases do not form clatrate compounds?
        The small sized helium and neon do not form clathrate compounds whereas Ar, Kr and Xe do form.
Which noble gas can form interstitial compounds with metals?
        Only helium forms interstitial compounds with metals.
What is the utility of clathrate formation?
Clathrate formation help in the separation of noble gases.
For,  example, Neon can be separated from Argon, krypton and Xenon by forming clathrate with quinol. Neon does not form clathrate with quinol.
How will you justify the inclusion of noble gases in the zero group of the periodic table?
        The long form periodic table is based upon filling of last electrons in various shell of element. Noble gases due to their ns2 np6 configuration are expected to be placed in the p-block of the periodic table after the members of the halogen family. These elements due to their stable configuration do not have normally any tendency to either lose gain or share electrons. As a result, there valence is zero and therefore, they are said to belong to zero group of the periodic table.
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