Atomic number and mass number

                                        Atomic number
The number of protron in the nucleus is called atomic number.
Representation:
                           It is representedby Z.
The charge on the nucleus  of an atom is equal to the number of protron.
       
                                        Mass number
The total number of proton and neutron  in an atom is called mass number.

Representation:
                           It is represented by A.
It also determines the mass of the nucleus.
             
                     Symbolic representation of an elements 
A-Z=number of proton
                              
                                Physical properties
Those properties which are associated with the physical state of matter are called physical properties.
For examples:

1.                         Melting point 
2.                         Boiling point
3.                         smell
4.                         taste

                              Chemical properties
Those properties which depends upon the composition othe substance are called chemical properties.

For examples:
                        Burning coal is an example of chemical change