Which of the following best describes the chemical reactivity of the noble gases?

• A. They are moderately reactive and commonly form ionic compounds.
• B. They are generally unreactive due to their full valence electron shells.
• C. They react only with alkali metals under standard conditions.
• D. They are highly reactive and readily form compounds with most elements.

Answer: (B)

Verified step by step guidance

1. Understand that chemical reactivity is largely determined by the electron configuration of an element, especially the valence (outermost) electrons.
2. Recall that noble gases have a full valence electron shell, which means their outermost energy level is complete and stable.
3. Recognize that a full valence shell makes atoms less likely to gain, lose, or share electrons, leading to very low chemical reactivity.
4. Compare this to other elements that have incomplete valence shells and tend to react to achieve a stable electron configuration.
5. Conclude that noble gases are generally unreactive because their full valence electron shells make them stable and unlikely to form compounds under normal conditions.