Identify the species

The given options are noble gases: $\text{He},\ \text{Ne},\ \text{Kr},\ \text{Xe}$

Recall the factor affecting boiling point in noble gases

Noble gases are monoatomic and nonpolar, so the main intermolecular force between their atoms is London dispersion force.

The strength of London dispersion forces increases with:

• larger atomic size
• greater number of electrons
• higher polarizability

Compare the noble gases

Going down the group: $\text{He} < \text{Ne} < \text{Kr} < \text{Xe}$

Atomic size and polarizability increase down the group, so intermolecular attraction becomes stronger.

Infer boiling point order

Stronger intermolecular forces mean a higher boiling point. Therefore: $\text{He} < \text{Ne} < \text{Kr} < \text{Xe}$ in boiling point as well.

Evaluate options

• A: Ne — not highest
• B: Kr — high, but less than Xe
• C: Xe — highest boiling point
• D: He — lowest

Final answer

$\boxed{\text{Xe}}$

Comparison with stored correct answer

Stored correct answer: C

Derived answer: C

They match.