mp = 12. 1,6726.10-27 kg = 20,0712.10-27kg
me = 12.9,1094.10-31kg = 109,3128.10-31kg\(\approx\)0,01093128.10-27kg
mn = 12. 1,6748.10-27 kg = 20,0976.10-27kg
mhn = mp + mn = 40,01688.10-27kg.
mngt= mhn + me \(\approx\) 40,0278.10-27kg.
mngt \(\approx\) mhn