The mass of an atom is 6 amu that has 3 electrons, 3 protons, and 3 neutrons.
The mass number is defined as the total number of protons and neutrons in an atom. It is represented by the letter A. When we sum number of proton and neutron present in an atom we get mass number.
So we can conclude that the mass of an atom is 6 amu that has 3 electrons, 3 protons, and 3 neutrons.
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