Which statement about noble gases is true?

• A. They are reactive.
• B. They are inert because they have full outer shells.
• C. They form diatomic molecules.
• D. They readily accept electrons to form bonds.

Answer: (B)

Noble gases are inert because their outer electron shells are already full. A full valence shell means atoms have no strong drive to gain, lose, or share electrons to reach a more stable configuration, so they don’t readily form bonds. That’s why they exist as stable, monatomic gases and show very low reactivity. The statement that they are inert due to full outer shells is the correct one. The other ideas—being reactive, forming diatomic molecules, or readily accepting electrons to bond—do not describe their usual behavior. (Note: under extreme conditions a few heavy noble gases can form rare compounds, but these are exceptions to the general rule.)