Consider the following minor gases of the Earth atmosphere: 1. Argon 2. Neon 3. Helium 4. Carbon dioxide. Which one of the following shows these gases in the correct ascending order of their volume percentage in dry air?

Introduction / Context:
This question belongs to environmental chemistry and basic geography. It asks you to compare the relative abundances of some minor gases in the atmosphere of Earth. While nitrogen and oxygen dominate the air, trace gases like argon, carbon dioxide, neon and helium are also present in small but important quantities. Understanding their approximate volume percentages helps in interpreting discussions about climate and air composition.

Given Data / Assumptions:

• The gases listed are argon, neon, helium and carbon dioxide.
• We are dealing with volume percentage in dry air at ground level.
• We must arrange the gases in ascending order, that is, from lowest percentage to highest percentage.
• Nitrogen and oxygen are not part of this comparison; we focus only on the four given gases.

Concept / Approach:
Standard data for dry air show that argon is the most abundant of the listed gases, with a volume percentage close to 0.93 percent. Carbon dioxide is present at a lower level of roughly a few hundred parts per million, around 0.03 to 0.04 percent. Neon and helium are noble gases present in much smaller amounts, with helium being less abundant than neon. Therefore, from lowest to highest concentration, the order is helium, then neon, then carbon dioxide, and finally argon. We must map this order to the numerical labels given in the question: 3 for helium, 2 for neon, 4 for carbon dioxide, and 1 for argon.

Step-by-Step Solution:

Verification / Alternative check:
Standard composition tables of dry air list approximate volume percentages as nitrogen about 78 percent, oxygen about 21 percent, argon about 0.93 percent and carbon dioxide about 0.03 to 0.04 percent. Neon and helium are far lower, in the parts per million or less range, with helium generally the least abundant among the four considered here. If you place these values on a number line, helium is at the lowest end, then neon, then carbon dioxide, and finally argon. Comparing this sequence with the coded labels confirms that 3 - 2 - 4 - 1 is the correct ascending order.

Why Other Options Are Wrong:

• 2 - 3 - 4 - 1: This places neon before helium, but helium is actually less abundant than neon.
• 4 - 2 - 3 - 1: This places carbon dioxide at the lowest concentration, which is incorrect because noble gases like helium and neon are present in smaller amounts than carbon dioxide.
• 2 - 4 - 1 - 3: This wrongly places argon before helium, suggesting that helium is more abundant, which is not true.
• 1 - 4 - 2 - 3: This option starts with argon and ends with helium, which completely reverses the expected order for trace gases.

Common Pitfalls:
Many learners overestimate the amount of carbon dioxide in air because climate discussions focus heavily on its importance. As a result, they sometimes think that carbon dioxide is more abundant than argon. In reality, argon, although chemically inert, is more abundant by volume. Another mistake is to assume that all noble gases must have very similar abundances. However, helium and neon occur in very small concentrations compared to argon and carbon dioxide. Keeping approximate percentage values in mind will help avoid these misconceptions.

Final Answer:
The correct ascending order of volume percentage for the given gases is 3 - 2 - 4 - 1, that is helium, neon, carbon dioxide and then argon.