Kaplan Nursing Entrance Practice Exam

What characteristic defines inert gases?

1. They easily react with other elements

2. They have full valence electron shells

3. They are all liquids at room temperature

4. They are all highly flammable

The correct answer is: They have full valence electron shells

The characteristic that defines inert gases is that they have full valence electron shells. This property is a result of their electron configurations, which make them extremely stable. Inert gases, also known as noble gases, include helium, neon, argon, krypton, xenon, and radon. Because their outermost energy levels are filled, there is little tendency for these gases to gain or lose electrons, leading to their lack of reactivity under standard conditions. This stability is what distinguishes them from other elements that readily interact with each other to achieve full valence shells. Elements with incomplete valence shells typically seek out reactions to attain stability, while inert gases do not need to ionize or share electrons. As such, they are often found in their elemental form in nature and are employed in applications requiring non-reactive environments, like in lighting and various industrial processes. In contrast, the other statements are not true for inert gases. They do not easily react with other elements, they include gases at room temperature rather than all being liquids, and they are not flammable. These properties further illustrate the unique and stable nature of inert gases compared to more reactive substances.