JAMB Chemistry 2021 Paper

Concept:Rare gases are the noble gases present in the atmosphere. The most abundant of them all is argon.Explanation:Air is made up mostly of nitrogen, $\mathrm{N}_2$, which is about 78% of the atmosphere.Oxygen, $\mathrm{O}_2$, is the second most abundant gas, occupying about 21%.Among the rare gases, argon, $\mathrm{Ar}$, is the most plentiful.Argon has an atomic number of 18 and makes up nearly 0.93% of the atmosphere.This is higher than the amounts of helium, $\mathrm{He}$, neon, $\mathrm{Ne}$, and xenon, $\mathrm{Xe}$, found in air.Therefore, argon is the most abundant rare gas in the atmosphere.Answer:C. Ar