Which gases are classified as inert?

Inert gases are those that do not readily react with other substances under standard conditions. Argon and helium are classified as inert because they belong to the noble gases category. These gases have a complete electron shell, which makes them stable and unlikely to form chemical bonds with other elements.

Argon, being abundant in the atmosphere, is commonly used in welding processes to provide an inert atmosphere, particularly in processes like TIG welding. Helium is also used in certain welding applications due to its high thermal conductivity and ability to stabilize the arc during the welding process.

Other choices include gases like oxygen and carbon dioxide, which are reactive and participate in combustion and oxidation reactions, disqualifying them from being classified as inert. Thus, the choice of argon and helium showcases the correct identification of gases that maintain their stability and do not participate in chemical reactions under typical circumstances.