A pure substance whose molecules contain two or more atoms, combined together in a definite ratio is called compound.
State the terms :
(a) Substances whose atoms or molecules are arranged in a definite pattern.
(b) Different forms of an element found in the same physical state.
(c) The property by which atoms of an element link together to form long chain or ring compounds.
Two or more atoms joined together chemically in a fixed proportion by mass are called molecules.