What are inactive gases?

It seems there might be a slight misunderstanding in your question. In chemistry and physics, there is no specific category of "inactive gases." However, you might be referring to "noble gases" or "inert gases," which are two different terms used to describe a group of gases with low reactivity.

Noble gases, which include elements like helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn), are known for their low chemical reactivity. They are called "noble" because they were once thought to be completely inert due to their very stable electron configurations. These gases have a full complement of electrons in their outermost energy levels, making them highly stable and unreactive with other elements under normal conditions.

Inert gases, on the other hand, are a broader category that includes not only the noble gases but also some other gases, such as nitrogen (N2) and carbon dioxide (CO2), in certain contexts. Inert gases are called so because they generally do not undergo chemical reactions or participate in combustion easily. They are often used in various industrial applications, such as welding and as protective atmospheres in chemical processes.

So, while "inactive gases" is not a standard term in chemistry or physics, you may be thinking of noble gases or inert gases, both of which describe gases with low reactivity.