Question

Justiflty or cruricize althrought the usobar have mass number their massas are not exactly same ?​

Answer 1

Answer: this is because the mass of a neutron is not exactly the same as that of a proton, a neutron is slightly more heavy. ... There are mass spectrometers sensitive enough to measure a hundredth of a mass number, and those are able to differientiate between these two molecules.