* Noble gas molecules are monatomic, meaning they consist of a single atom.

* Atom gas refers to a gas made up of individual atoms, which is the case with noble gases.

Here's why:

* Noble gases are very unreactive because their outer electron shells are full. This makes them stable and they don't readily form chemical bonds with other atoms.

* A molecule is formed when two or more atoms bond together. Since noble gases don't readily bond, they exist as individual atoms in the gaseous state.

Therefore, a noble gas molecule is essentially the same as a noble gas atom.