Why are certain elements referred to as 'noble gases'?

Certain elements are referred to as 'noble gases' because they are very stable and rarely react with other elements.

Noble gases, also known as inert gases, are a group of chemical elements that are characterised by their low reactivity. This group includes helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). They are located in Group 18 (VIII A) of the periodic table and are the most stable due to their full electron configuration.

The term 'noble' is derived from the analogy to nobility in human societies, who historically have been reluctant to interact with commoners. Similarly, noble gases are reluctant to engage in chemical reactions with other elements. This is because they have a full valence electron shell, which is the most stable configuration. As a result, they have little tendency to gain or lose electrons, making them highly unreactive.

The stability and low reactivity of noble gases make them incredibly useful in various applications where reactions are undesirable. For example, argon is used in light bulbs to prevent the filament from oxidising, and helium is used in balloons and airships as it is lighter than air and non-flammable.

However, it's worth noting that the term 'inert' is somewhat of a misnomer. While noble gases are indeed less reactive than most other elements, they are not completely unreactive. Under certain conditions, such as high pressure or when exposed to an electric field, noble gases can and do form compounds. For instance, xenon hexafluoride (XeF6) is a compound of xenon, one of the noble gases, and fluorine.

In summary, the term 'noble gases' is used to describe a group of elements in the periodic table that are characterised by their low reactivity due to their full valence electron shell. This makes them stable and less likely to engage in chemical reactions, much like nobility in human societies.