Whether something is a molecule or not depends on the type of bond that is formed when its atoms join together. In general, electrons can be shared between atoms (a molecular bond) or electrons can be completely removed from one atom and given to another (an ionic bond). Molecules have molecular bonds.
Whether something is a compound or not depends on how many different kinds of elements make it up. Compounds contain two or more different elements.
Water is a molecule because it contains molecular bonds. Water is also a compound because it is made from more than one kind of element (oxygen and hydrogen). If you like, you can say that water is a molecular compound.
Something like table salt (NaCl) is a compound because it is made from more than one kind of element (sodium and chlorine), but it is not a molecule because the bond that holds NaCl together is an ionic bond. If you like, you can say that sodium chloride is an ionic compound.
Oxygen in the atmosphere is a molecule because it contains molecular bonds. It is not a compound because it is made from atoms of only one element - oxygen. This type of molecule is called a diatomic molecule, a molecule made from two atoms of the same type.
Explanation:
A compound is defined as the substance that contains two or more different atoms that are chemically combined to each other in a fixed ratio by mass.
For example, [tex]CaCl_{2}[/tex], [tex]H_{2}O[/tex], [tex]AlCl_{3}[/tex] etc are all compounds.
On the other hand, a molecule only contains two or more atoms of same element which are chemically combined to each other.
For example, [tex]Cl_{2}[/tex], [tex]H_{2}[/tex] etc are all molecules.
A molecule is the sub-unit of a compound.
Thus, we can conclude that the correct statements regarding a compound and a molecule are as follows.
