Question

Answer the following with relevant reason. 

(i) Why the zero group elements do not form compounds under ordinary conditions ? 

(ii) Xenon has closed shell configuration but is known to give compounds with fluorine. 

(iii) The boiling points of noble gases increase with increase in atomic number. 

(iv) A mixture of He and O₂ is used for respiration by sea divers. 

(v) Why helium and neon do not form clathrate compounds with quninol ?

Answer 1

(i) Zero group elements have complete electronic configuration of their outer shells, i.e. ns²np⁶ (except helium which has 1s²), hence they do not have any tendency either to lose or accept electron/ electrons or share electrons with other atoms. 

(ii) Xe has relatively lower ionisation energy among inert gases and thus the outermost shell electrons of Xe are excited to d-subshell and thereby showing unpaired electronic structure. Therefore Xe shows covalent bonding with fluorine showing sharing of electron pair. 

(iii) Van der Waal’s forces of attraction among molecules increase with the increase of atomic masses. Thus, higher energy is required to separate these molecules as to get gaseous state. Hence, the boiling points increase with increase of atomic masses. 

(iv) Unlike nitrogen, helium is not soluble in blood even under high pressure. 

(v) The size of cavities formed during crystallisation of quinol is more than the size of helium and neon atoms.