Vitamin B12, also known as cyanocobalamin, is a water-soluble vitamin that is part of the B vitamin family. B vitamins help support adrenal function, help calm and maintain a healthy nervous system, and are necessary for key metabolic processes.
For each of the 80 stable elements, the number of the stable isotopes is given. Only 90 isotopes are expected to be perfectly stable, and an additional 163 are energetically unstable, but have never been observed to decay. Thus, 253 isotopes (nuclides) are stable by definition (including tantalum-180m, for which no decay has yet been observed).
The number of neutrons a nucleus can hold differs from element to element. Among these isotopes, only some are stable. For instance, oxygen has three stable isotopes, and tin has ten stable isotopes. Most of the time, simple elements have same neutron number as the proton number. But in heavy elements, more neutrons are there than the protons.