1. The problem asks to identify one way in which the Nobel Gases (group 18 elements) differ from other elements on the Periodic Table of Elements (PTOE). 2. Nobel Gases are known for their unique chemical properties compared to other elements. 3. Important rule: Nobel Gases have a full outer electron shell, which makes them very stable and unreactive. 4. Let's analyze the options: - High atomic masses: Not unique to Nobel Gases; other elements can have high atomic masses. - High boiling points: Nobel Gases generally have low boiling points. - Highly reactive: Nobel Gases are actually very unreactive. - Highly stable: This is true because their full outer shells make them chemically inert. 5. Therefore, the correct answer is: Nobel gases are highly stable. Final answer: **Nobel gases are highly stable**.