- An element is pure substance formed by same kind of atoms (Having same atomic numbers). Examples of elements are Hydrogen, Oxygen, Carbon, Iron, Sodium etc.
- There are only 118 elements in the world. Thus number of elements in the world is limited.
- An element can’t be broken down into two or more simpler substances by any method.
- Every element has a unique atomic number. Thus different elements can’t have same atomic number. For example of atomic number of hydrogen is 1.
- Every element possess some physical and chemical properties.
- When two are or more atoms of different elements reacts chemically in a fixed ratio then new substance formed is called compound. Examples of compounds are NaCl, HCl, H2O and CH4.
- The number of compounds are unlimited.
- A compound can be broken down into its constitute atoms.
- Compounds have only molecular mass. For example molecular mass of NaCl is 58.44 gram per mole.
- Physical and chemical properties of a compound are different from those of its constituent elements.