Does the mass of an atom changes due to transfer of electron

Answers (1)

Lets first write the masses of electron, proton, and neutrons

mass of electron = 9.1\times 10^{-31} kg

Mass of neutron and proton, = 1.67\times 10^{-27} kg

Now you can see that mass of neutron or proton is 10000 times the mass of the electron and we know that the nuclei of an atom comprises of neutron and proton. 

To answer the question that whether the mass of atom will change or not, Yes it will be changed but it will not be significant because the mass of nuclei is around 20000 times the mass of electrons.