Noble gases are named because of their inertness towards reactivity. Identify an incorrect statement about them.

**Why this statement is incorrect**

The noble gases (He, Ne, Ar, Kr, Xe, Rn) are located in Group 18 of the periodic table. Their outer electron shells are completely filled, which makes them chemically inert. Because of this electronic configuration, the only forces that hold the atoms together in the solid or liquid phase are the very weak London‑dispersion (van der Waals) forces.

Dispersion forces increase with the size and polarizability of the atoms. Among the noble gases, the forces grow from helium to radon, but even for the heaviest (radon) they remain far weaker than the ionic, covalent, or metallic bonds found in most other elements. Consequently, the amount of energy required to break these attractions—and thus the temperatures at which the substances melt or boil—are extremely low.

Experimental data confirm this trend:

• Helium: melting point ≈ ‑272 °C, boiling point ≈ ‑269 °C
• Neon: melting point ≈ ‑249 °C, boiling point ≈ ‑246 °C
• Argon: melting point ≈ ‑189 °C, boiling point ≈ ‑186 °C
• Krypton: melting point ≈ ‑157 °C, boiling point ≈ ‑152 °C
• Xenon: melting point ≈ ‑112 °C, boiling point ≈ ‑108 °C
• Radon: melting point ≈ ‑71 °C, boiling point ≈ ‑62 °C

All of these temperatures are well below room temperature, illustrating that noble gases have **low**—not high—melting and boiling points. Therefore the statement “Noble gases have very high melting and boiling points.” is the incorrect option among the choices.

**Comparison with other options**

1. *Weak dispersion forces* – true, because the only intermolecular attraction present is the weak London‑dispersion force.

2. *Large positive electron‑gain enthalpy* – true; noble gases do not readily gain electrons, so the electron‑gain enthalpy values are positive and relatively large.

3. *Sparingly soluble in water* – true; the lack of polarity and weak intermolecular forces lead to very low solubility in polar solvents like water.

Only the claim about very high melting and boiling points contradicts the known physical data, making it the incorrect statement.