Gas is one of the three physical states substances are known to occur in. The other two are solid and liquid. Gases are classified into two: inert and noble.
Inert gases are non-reactive gases in that they do not undergo chemical reactions. Generally, atoms react with other chemical species by either filling all the electron shells or taking away the electrons located in the outermost shell. This process is what helps keep it stable. The non-reactive quality of inert gases is due to the fact that the valence shells of inert gases are complete. This means these gases have atoms with electron shells that are completely filled so there is no need to react with other chemical species.
Because inert gases are non-reactive, they are often used in certain situations to keep unwanted chemical reactions from happening.
Examples of how inert gases are used:
- As a food preservative, inert gases can be used in the packages to keep oil from becoming rancid.
- Inert gases like humidified argon is used to protect important historical documents from degradation.
- Inert gases are also used to purge transfer lines and vessels to keep residual process fluids and solvents from catching fire in oil refineries and other plants.
Belonging to the group 18 of the periodic table of elements, noble gases have very low to no reactivity. There are six noble gases, namely argon, helium, krypton, neon, radon, and xenon. These monoatomic gases, which are odorless and colorless, possess valence shells that are completely filled, a characteristic that makes noble gases quite unreactive. However, these gases can be made to react or be turned into compounds under extreme conditions, except for helium and neon, which do not undergo chemical bonding. On the other hand, argon, krypton, and xenon can form chemical bonds since these gases are weakly reactive. Radon is a radioactive element.
Summary of differences:
Under ordinary conditions, both inert and noble gases are non-reactive. However, noble gases can be made to react under extreme condition. While all noble gases are inert gases, not all inert gases are noble gases.