Step-by-step explanation:
A molecule is a substance that contains atoms of either different or same elements.
For example,
molecule and NaCl is also a molecule.
On the other hand, a compound always consists atoms of different elements. For example, NaCl is also a compound but
is not a compound.
Whereas it is known that gases exist as diatomic molecules. For example,
,
,
are all gases.
Therefore, we can conclude that the particles of a gas are molecules.