Which of the following best explains why noble gases are generally nonreactive?

• A. They have completely filled valence electron shells, making them chemically stable.
• B. They have high electronegativity, preventing them from forming bonds.
• C. They are metals and therefore do not react with other elements.
• D. They have low atomic masses, so they do not interact with other elements.

Answer: (A)

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 having a full valence shell of electrons, which means their outermost energy level is completely filled.
3. Recognize that a full valence shell corresponds to a very stable electronic arrangement, which makes atoms less likely to gain, lose, or share electrons to form chemical bonds.
4. Evaluate the other options: high electronegativity is not characteristic of noble gases; noble gases are nonmetals, not metals; and atomic mass does not directly determine chemical reactivity.
5. Conclude that the best explanation for the nonreactivity of noble gases is their completely filled valence electron shells, which confer chemical stability.