H2 is indeed a molecule, but H2O is a compound.
To break it down:
- H2: This is a diatomic molecule composed of two hydrogen atoms. It is the simplest form of a molecule, consisting only of hydrogen.
- H2O: This is a compound formed from two hydrogen atoms and one oxygen atom. It is a molecular compound, meaning it is made up of different types of atoms bonded together.
So the correct answer is b) compound. The term ‘diatomic molecule’ typically refers to molecules made up of two atoms of the same element like H2. H2O, however, cannot be classified as just a diatomic molecule because it contains different types of atoms and is a compound.