Noble gases, such as helium and neon, have stable, outer level electron configurations. How does this fact explain why atoms of noble gases usually do not form chemical bonds?
Stable atoms means no bonds can be formed, and since Noble Gases are stable, they cannot react... most of the time.
The term "stable" in Chemistry simply means that the atoms have an octet shell. With a full valence shell, electrons cannot be shared nor transferred. Since Noble Gases are known to be stable, it means they do not react with other elements, unless in special circumstances.
Of the Noble Gases, only Helium and Neon are truly stable - the other noble gases will react under very special conditions: Krypton will form a solid with Fluorine, and Xenon will form an assortment of compounds with Oxygen and Fluorine.
In general, we classify the Noble Gases to be the least reactive, rather than stable, but it is acceptable by most institutions to say stable.
Hope this helps :)