The preservation of invaluable historical documents is achieved by sealing them in specialized glass display cases backfilled with pressurized argon gas (Ar\text{Ar}Ar) rather than air or helium (He\text{He}He).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.
Practise Edexcel GCSE Chemistry Group 0 with exam-style questions for Foundation and Higher tier. 30 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.