# Which corner of the isotope symbol contains the mass number?

When we write ${\text{^12}}_{6} C$, the bottom left symbol is the atomic number $Z$; the top left smbol is the mass number. Since the elemental symbol, the $C$, automatically specifies the atomic number $Z = 6$, it is redundant, and may be discarded to give just ""^12C. Reading this symbol, this tells us that we deal with a nucleon with 6 neutrons in the nucleus, 6 massive, neutrally charged, nucular particles.
For the ""^13C and ""^14C isotopes, how many neutrons in each such atom? And how many electrons? Why?