Final answer:
Argon is approximately 10 times heavier than helium, so none of the provided options correctly describes how much heavier argon is compared to helium.
Step-by-step explanation:
When comparing the density of shielding gases, argon is significantly heavier than helium. The atomic weight of helium is approximately 4.00 g/mol, while the atomic weight of argon is about 39.948 g/mol.
To find out how much heavier argon is compared to helium, you can divide the atomic weight of argon by that of helium: 39.948 g/mol ÷ 4.00 g/mol = 9.987, which is approximately 10 times heavier. However, the provided options do not include 10, and as such, none of the given options (A. 1, B. 2, C. 3, D. 4) is correct.