# What does the nucleus of an atom of cobalt-58 contains?

Well if it's ""^58Co, then the atom contains 27 protons.......
The element cobalt is characterzied by the presence of 27 massive, positively charged particles, $\text{27 protons}$, in its nucleus. Since it is ""^58Co, there are $\text{31 neutrons}$, 31 massive, neutrally charged particles in its nucleus.