Final answer:
The noble gases are a group of highly unreactive elements in Group 18 of the periodic table with filled valence shells; helium, neon, argon, krypton, xenon, and radon are all monatomic gases at room temperature and have applications like lighting and coolants.
Step-by-step explanation:
Properties of Noble Gases
The noble gases, also known as group 18 or the inert gases, are a significant group in the periodic table. The group comprises helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). These elements are characterized by having filled valence electron shells, which confer stability and make them highly unreactive under normal conditions.
Their unreactivity is a reason why they do not form compounds easily. However, exceptions exist under extreme conditions. The heavier noble gases, such as xenon, can form compounds with fluorine. They are all monatomic gases at room temperature due to the high stability of their electron configurations. Noble gases have a variety of applications, including providing inert atmospheres for industrial processes, lighting (as in neon signs), and as coolants.
Helium, with a full shell of two s electrons, is particularly noteworthy because it is extremely difficult to remove these electrons due to the absence of electron shielding from the nucleus. This makes helium one of the most unreactive elements. Despite the noble gases' reputation for inactivity, some, like xenon, have been used to form stable fluorides, which serve as starting materials for creating other noble gas compounds.