The preservation of invaluable historical documents is achieved by sealing them in specialized glass display cases backfilled with pressurized argon gas (Ar\text{Ar}Ar) rather than air or helium (He\text{He}He).
Which statement correctly explains the chemical and physical basis for choosing argon over air and helium for this application?
Argon is chemically inert due to its stable 3s23p63s^2 3p^63s23p6 valence electron configuration, preventing oxidation of the document, and its larger atomic size and mass compared to helium result in a slower rate of effusion (leakage) through microscopic seals.
Argon is preferred because it has a lower first ionisation energy than helium, which makes it less reactive and more chemically stable under all conditions.
Argon has a stable 2s22p62s^2 2p^62s22p6 outer shell configuration, which prevents it from forming any instantaneous dipole-induced dipole forces with the document fibres.
Argon has a lower density than helium, ensuring that the buoyant force inside the glass case minimizes the gravitational stress on the fragile parchment.
44 exam-style questions on Edexcel GCSE Chemistry 7.3 Group 0, covering 7.3.1 The noble gases. Each one has a worked solution and a mark scheme showing where the marks go.