Assertion: hydrogen's isotope | /r/MadeOf | neutron
Facets:
Source sentences:
text: The most abundant isotope, hydrogen-1, protium, or light hydrogen, contains no neutrons and is simply a proton and an electron.
text: (However, an isotope of hydrogen, called deuterium, contains one protron and one neutron, and another, known as tritium, has one proton and two neutrons.)