Which of the following best explains why noble gases are generally unreactive with other elements?

• A. They have very low atomic radii, preventing them from interacting with other atoms.
• B. They have completely filled valence electron shells, making them chemically stable.
• C. They readily lose electrons to form positive ions.
• D. They have the highest metallic character among all 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 electrons in the outermost shell, called valence electrons.
2. Recall that noble gases are located in Group 18 of the periodic table and are known for their unique electron configurations.
3. Recognize that noble gases have completely filled valence electron shells, meaning their outermost energy level is full of electrons, which makes them very stable and unlikely to gain, lose, or share electrons.
4. Note that because their valence shells are full, noble gases have little tendency to react with other elements, unlike elements that seek to fill or empty their valence shells to achieve stability.
5. Conclude that the best explanation for the low reactivity of noble gases is their completely filled valence electron shells, which confer chemical stability.