Among the following, which is a common property of noble gases?

• A. Highly reactive
• B. Colorless and odorless
• C. Metallic luster
• D. Conductive

Answer: (B)

Noble gases are known for their unique properties due to their complete valence electron shells, which greatly contribute to their stability and lack of reactivity. One of the most notable common properties of noble gases is that they are colorless and odorless. This characteristic makes them difficult to detect without specialized instruments, as they do not exhibit any color or smell when in their gaseous states.

This property is integral to the nature of these gases, as they do not engage in chemical reactions under standard conditions, leading to a lack of any detectable color or odor, which is essential for their applications and identifications in various scientific contexts. Their inert nature also means that they do not form compounds easily, which is another reason why they remain colorless and odorless.

The other choices reflect characteristics that do not apply to noble gases: they are not highly reactive, do not exhibit metallic luster (as they are gases at room temperature), and are typically poor conductors of electricity, further highlighting their unique status among elements in the periodic table.