Six elemental gases are composed of such exceptionally stable atoms that they almost never react with other elements. They are the gases that make up Group 0 (the rightmost column) of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
D) Radioactive contamination
Answer:
number of moles=volume/molar volume or mass/molar mass
I think it's 2 I tried looking it up because I was not sure.
I think it is C. coefficients but I don't know what subscripts are