The number of neutrons in the isotope of sodium is 14 due to 11 number of protons.
We know that atomic number of sodium is 11 which means sodium has 11 protons in its nucleus so if the atomic mass is 25 then 25 -11 is equals to 14.
So we can conclude that an isotope of sodium with a mass number of 25 has 14 electrons in its nucleus because there are 11 protons are present in the nucleus of sodium atom.
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