Cyanocobalamin is the most common and widely produced form of the chemical compounds that have vitamin B12 activity.
For example, the hadron constituents of atomic nuclei, neutrons and protons, have charges of 0 e and +1 e respectively; the neutron is composed of two down quarks and one up quark, and the proton of two up quarks and one down quark.
The number of neutrons is the mass number minus the atomic number, that is 56 - 26, so there are 30 neutrons in the nucleus. For a neutral atom, the number of electrons in orbit must be exactly equal to the number of protons present in the nucleus, so the number of electrons in this neutral atom is also 26.