Question

Assertion:
(A): Noble gases have very low boiling points.
Reason:
(R): All noble gases have general electronic configuration of $n{s^2}n{p^6}$(except$He$)
(A) Both (A) and (R) are true but (R) is correct explanation of (A)
(B) (A) is false but (R) is true
(C) (A) is true but (R) is false
(D) Both (A) and (R) are true but (R) is not the correct explanation of (A)

Answer 1

Hint: Noble gases have weak Vander waals forces present in them both in the liquid and solid state. and have very low melting and boiling point due to this reason.

Complete step by step answer:
Noble gases are the elements of group $18$ of the periodic table. These are also referred to as inert gases as these are least reactive ones. These are the most stable due to the presence of maximum number of valence electrons in their outer shells.
      The Noble Gases are:
Helium $ \to 1{s^2}$
Neon $ \to \left[ {He} \right]2{s^2}2{p^6}$
Krypton $ \to \left[ {Ar} \right]3{d^{10}}4{s^2}4{p^6}$
Xenon $ \to \left[ {Kr} \right]4{d^{10}}5{s^2}5{p^6}$
Radon $ \to \left[ {Xe} \right]4{f^{14}}5{d^{10}}6{s^2}6{p^6}$
Argon $ \to \left[ {Ne} \right]3{s^2}3{p^6}$
The general electronic configuration of noble gases is $n{s^2}n{p^6}$(except$He$).

Some of Properties of Noble Gases are:
Atomic mass, boiling point and atomic radii increases down the group in the periodic table.
Down the group $18$, atomic radius and interatomic forces increase resulting in an increased melting point, boiling point, solubility and enthalpy of vaporization
Under standard conditions all members of the noble gases behave similarly.
The Melting Points and boiling Points of noble gases are low as compared with the substances having comparable molecular masses. This shows that the weak dispersion forces are present between the atoms of noble gases.
The weak Vander waals forces increase with increase in size of atom and hence, the boiling point increases from $He$ to$Rn$.
Both the assertion and reason are a correct statement but they are not related to each other.



So, the correct answer is Option D.

Note:
Increased dispersion forces the boiling point and melting points of noble gases increases from $He$ to $Rn$.