Which statement explains why noble gases are unreactive?

Which statement explains why noble gases are unreactive?

• A. They are diatomic molecules
• B. Full outer electron shells
• C. They have high melting points
• D. They easily react with oxygen

Answer: (D)

The key idea is that noble gases have full outer electron shells, giving them highly stable electron configurations. With a complete valence shell (eight electrons for most, helium with two), there’s no drive to gain, lose, or share electrons to form bonds. That stability means they don’t readily participate in chemical reactions, so they stay unreactive under normal conditions. The other statements don’t fit: noble gases are not diatomic and exist as single atoms in their elemental form; they have very low melting points due to weak interatomic forces; and they do not readily react with oxygen (or most other elements) except under special high-energy conditions.

The key idea is that noble gases have full outer electron shells, giving them highly stable electron configurations. With a complete valence shell (eight electrons for most, helium with two), there’s no drive to gain, lose, or share electrons to form bonds. That stability means they don’t readily participate in chemical reactions, so they stay unreactive under normal conditions.

The other statements don’t fit: noble gases are not diatomic and exist as single atoms in their elemental form; they have very low melting points due to weak interatomic forces; and they do not readily react with oxygen (or most other elements) except under special high-energy conditions.