Answer : There are mainly three isotopes of magnesium found in nature; namely Mg-24, Mg-25 and Mg-26. Out of which Mg-24 has 12 neutrons, Mg-25 has 13 neutrons and Mg-26 has 14 neutrons in their atoms. The number of protons and their atomic masses remains the same for the atom. The relative abundance in nature differs for all the three isotopes. Mg-24 has abundance nearly 80% in nature, Mg-25 has abundance as 10% and Mg-26 has 11.01% abundance.