Does the person who wrote this know about how lightbulbs work? The stuff inside a lightbulb that isn't the wire has to be nonreactive, or your lightbulb explodes. And if you fill it with a vacuum, then it will implode instead if you just tap it. You know what is entirely unreactive, is cheap to produce, and is naturally as dense as air? Argon.
But if the submitter is not happy with their "request" for one thing argon does being answered, well argon also barely conducts heat. This makes it useful for so many industrial applications. It also is used to date the ages of rocks and ice, as a preservative for many chemicals as well as types of wine, for detecting neutrinos which if you know anything about them you would know how impressive that is, and to create lasers. It is used to store important historical documents, like the American declaration of independence, or that same countries constitution, which regardless of how you feel about the country in question, it's still a job with a lot of significance. Liquid argon has been used to kill cancer, and has been banned by the World Anti-Doping Agency.
I do understand if it wins against (is worse than) carbon this round, because it is carbon, but if it does well in the tournament because it is useless and unknown, even though as you can see earlier is has so many uses, and most people would agree that it is better known than many of the other competitors. So don't vote argon.