The Group 18 elements (He, Ne, Ar, Kr, Xe, Rn) are commonly known as

The Group 18 elements (He, Ne, Ar, Kr, Xe, Rn) are commonly known as

• A. Noble gases
• B. Noble-gas configuration
• C. Electron configuration
• D. Chemical bonding

Answer: (A)

Filled valence shells give these elements extreme stability and very low reactivity, which is why Group 18 elements are called noble gases. Each has a complete outer shell (helium with 1s^2, the others with ns^2 np^6), so they rarely gain or lose electrons and almost never form bonds under ordinary conditions. They exist as colorless, odorless monoatomic gases at room temperature. The other options refer to electron configurations or bonding in general, not the family name for these elements.

Filled valence shells give these elements extreme stability and very low reactivity, which is why Group 18 elements are called noble gases. Each has a complete outer shell (helium with 1s^2, the others with ns^2 np^6), so they rarely gain or lose electrons and almost never form bonds under ordinary conditions. They exist as colorless, odorless monoatomic gases at room temperature. The other options refer to electron configurations or bonding in general, not the family name for these elements.