Element is a substance that cannot be broken further into simpler substances and has a definite set of properties. Elements are made up of only one kind of atom. Elements are the basic substances from which all other substances (compounds and mixtures) are made. They are widely distributed in the earth's crust in the free state as well as in combined states. At present 118 elements are known, out of which 92 are naturally occurring, while the rest 26 are artificially created.

Compounds are pure substances composed of two or more elements in definite proportion by mass and have properties, entirely different from those of their constituents elements. Compounds are made up of different types of atoms combined chemically to form molecules.