What term describes very unreactive elements in the periodic table?

What term describes very unreactive elements in the periodic table?

• A. Alkali metals
• B. Halogens
• C. Noble gases
• D. Transition metals

Answer: (C)

This question hinges on how electron arrangement affects reactivity. Very unreactive elements are described as noble gases. They have full outer electron shells, which makes them exceptionally stable and reluctant to gain or lose electrons. That stability gives them high ionization energies and almost zero tendency to form compounds under normal conditions, so they exist as monatomic gases. The other groups described—alkali metals are highly reactive with water, halogens are highly reactive nonmetals seeking electrons, and transition metals can be reactive and form many compounds—do not have this complete outer shell, so they aren’t inert. Noble gases is the correct term.

This question hinges on how electron arrangement affects reactivity. Very unreactive elements are described as noble gases. They have full outer electron shells, which makes them exceptionally stable and reluctant to gain or lose electrons. That stability gives them high ionization energies and almost zero tendency to form compounds under normal conditions, so they exist as monatomic gases. The other groups described—alkali metals are highly reactive with water, halogens are highly reactive nonmetals seeking electrons, and transition metals can be reactive and form many compounds—do not have this complete outer shell, so they aren’t inert. Noble gases is the correct term.