Noble gas periods of the periodic table, the noble gases are exactly the members of group 18. Noble gases are typically highly unreactive except when under particular extreme conditions. The inertness of noble gases makes them very suitable in applications where reactions are not wanted. For example, argon is used in incandescent lamps to prevent the hot tungsten filament from oxidizing; also, helium is used in breathing gas by deep-sea divers to prevent oxygen, nitrogen and carbon dioxide (hypercapnia) toxicity. The properties of the noble gases can be well explained by modern theories of atomic structure: their outer shell of valence electrons
Copia: Foundations of the Abundant Style 11 separate methods of using abundant subject matter. Here Erasmus uses a more dialectical approach, and typically gives a few lines of theory followed by many illustrations from classical sources. Erasmus purpose was to contribute to the existing scholarship on style. To that end, he put forth in "De Copia" that style must be abundant in order to be effective, and that the abundance consists of two primary elements: variety of expression and variety of subject matter. Variety, he says, “is so powerful in every sphere that there is absolutely nothing, however brilliant, which is not dimmed if not commended