Which of the following is a molecular monoatomic?

Argon is a noble gas and is monoatomic in nature, meaning it exists as individual atoms rather than forming molecules. Like other noble gases, argon is colorless, odorless, and chemically inert under most conditions, which means it does not easily react with other elements or compounds. Argon constitutes about 0.93% of the Earth's atmosphere by volume, making it the third most abundant gas in the atmosphere after nitrogen and oxygen. Its presence in the air is mainly due to the radioactive decay of potassium-40 in the Earth's crust.