Final answer:
Elements of Group 18 in the periodic table, known as the noble gases, are very unreactive due to their full outer electron shells that make them chemically inert.
Step-by-step explanation:
Based on its location in the periodic table, one could infer that elements of Group 18, also known as the noble gases, are very unreactive. The noble gases have a full outer shell consisting of two s electrons and six p electrons, totaling eight electrons in their valence shell. This electronic configuration is extremely stable, making noble gases chemically inert. The noble gases include helium, neon, argon, krypton, xenon, and radon. They are colorless, odorless, tasteless, and nonflammable under standard conditions. Historically referred to as 'inert gases', these elements rarely participate in chemical reactions and are usually found in their gaseous state in the atmosphere.
Noble gases have a completely filled outer shell of electrons, which makes them stable and less likely to form compounds with other elements. Their lack of reactivity is due to the fact that they already have a full complement of electrons, so they do not need to gain or lose electrons to achieve a stable configuration.