Question

Assertion (A): Noble gases have very low boiling points.

Reason (R): All noble gases have a general electronic configuration of $\text{n}{s}^2\text{n}{p}^6$ (except He).

Answer 1

Group 18

• The elements present in group 18 are helium, neon, argon, krypton, xenon, and radon.
• All these are gases and chemically unreactive.
• Only a few compounds are formed by these elements.
• As a result, they are referred to as noble gases.
• Their electronic configuration is $\text{n}{s}^2\text{n}{p}^6$ in general (except He).

Explanation for Assertion statement

• Due to minimal dispersion forces, noble gases have relatively low boiling points.
• Noble gases have extremely low melting and boiling temperatures when compared to other substances with similar atomic and molecular weights.
• This indicates that only weak van der Waals interactions or weak London dispersion forces exist between the atoms of noble gases in the liquid or solid state.
• In general, the boiling and melting points increase from $\mathrm{He}$ to $\mathrm{Rn}$ as the van der Waals force increases due to an increase in the size of the atom on going down the group.

Reason statement

• All noble gases have a general electronic configuration of $\text{n}{s}^2\text{n}{p}^6$ (except He).
• The given statement is true.

Hence, assertion and reason both are correct. But R is not the correct explanation of A.