CC5.3 — Noble gases (Edexcel 1SC0)

Noble gases: He, Ne, Ar, Kr, Xe, Rn

Group 0 elements have a full outer electron shell → extremely stable → do not form ions or covalent bonds → very unreactive (inert).

Physical properties

• All are colourless gases at room temperature.
• Monatomic (exist as single atoms, not molecules).
• Boiling points very low; increase down the group (larger atoms → stronger London dispersion forces).
• Density increases down the group.

Trend in boiling points

As atomic number increases:

• More electrons → larger electron cloud → stronger intermolecular forces (London dispersion/van der Waals).
• More energy needed to separate atoms → higher boiling point.

Uses