1.which are the fundamental particles whose masses are mainly responsible for the mass of an atom? give reasons ? 2.what is the mass of a Proton ?

3.what about the mass of a Neutron ?

4.what will be the mass of an atom having only one proton and one neutron ?

5.find the mass of an atom having two protons and two neutrons?

6.is there any relation between the total number of protons and neutrons in an atom and its mass ?

7.which is the fundamental particles of an atom that can be displaced when atoms rub against each other or they undergo chemical reaction with other atoms? give reasons ?​