Which of the following best explains why noble gases are generally unreactive, and which is an example of a noble gas?

• A. Noble gases have incomplete valence shells, making them highly reactive; neon is an example.
• B. Noble gases are unreactive because they have low atomic masses; argon is an example.
• C. Noble gases react easily due to their high electronegativity; helium is an example.
• D. Noble gases have a complete valence electron shell, making them chemically stable; xenon is an example.

Answer: (D)

Verified step by step guidance

1. Understand the electronic configuration of noble gases: Noble gases have a complete valence electron shell, which means their outermost energy level is fully occupied by electrons.
2. Recognize that a complete valence shell leads to chemical stability because atoms tend to gain, lose, or share electrons to achieve a full outer shell, and noble gases already have this configuration.
3. Identify that this full valence shell makes noble gases generally unreactive or inert, as they have little tendency to participate in chemical reactions.
4. Recall examples of noble gases, which include helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).
5. Match the correct explanation and example: The statement that noble gases have a complete valence electron shell making them chemically stable, with xenon as an example, best explains their unreactivity.