Which of the following is a characteristic of the noble gases?

• A. They readily form ionic compounds with alkali metals.
• B. They have high electrical conductivity in their elemental form.
• C. They are typically solid at room temperature.
• D. They are generally unreactive due to having a complete valence electron shell.

Answer: (D)

Verified step by step guidance

1. Recall that noble gases are elements found in Group 18 of the periodic table, such as helium, neon, and argon.
2. Understand that noble gases have a complete valence electron shell, which means their outermost electron energy level is full.
3. Recognize that having a full valence shell makes noble gases very stable and generally unreactive, as they do not need to gain, lose, or share electrons to achieve stability.
4. Evaluate the given options: they do not readily form ionic compounds because they are stable; they are gases at room temperature, not solids; and they do not have high electrical conductivity in elemental form.
5. Conclude that the key characteristic of noble gases is their general unreactivity due to their complete valence electron shell.