Molecules and their types

                       Molecule and their types

Molecule

       A molecule is the smallest particle in a chemical element or compound that has the chemical properties of that element or compound.

                                   

  

There are many types of molecules. Molecules are classified on different bases.

1. Classification on the base of numbers of atoms

On the basis of the number of atoms present in the molecule, it has the following types.

  Monoatomic:

                    If only one atom is present in a molecule then it is known as monoatomic.

 Example: He, C, Na

Polyatomic 

                  If more than one atom is present in molecules then it is known as polyatomic. It has further types like.

                Diatomic:

                             If two atoms are present, it is known as a diatomic Example.  H2 O2 Cl2, HCl.

                 Triatomic

                            If three atoms are present in a molecule then it is known as a triatomic example

H2O, Na2O.

2. Classification on the basis of types of atom

          On the basis of types of atoms, molecules have two types

          Heteroatomic

                               If different atoms are present in a molecule then it is known as heteroatomic molecules.  

Example:  HCl, NaOH.

          Homoatomic

                               If the same atoms are present in a molecule then it is known as the homoatomic molecule

Example.   H2, O2

3  Classification on the basis of molecular mass

on the basis of molecular mass, molecules have two types

   Macromolecules:

          If molecules have larger weight then it is known as macromolecules. 

Examples:        Nucleic acids, Protein, Hemoglobin, etc.

   Micromolecules

    If molecules have smaller weight then it is known as micromolecule. 

Example: water, ammonia, etc.

4. Classification on the basis of electronegativity difference

There are two types of molecules on the basis of electronegativity difference between the bonded atoms.

   Polar molecules

        If the electronegativity difference between the two bonding atoms is below 1.7 and above 1, then this molecule has polar nature.

 Example:   HCl

   Non-polar molecules

                       If the electronegativity difference between the bonding atoms is below 1, then this molecule has nonpolar nature. Example: CH4, C2H5