# When scientists look at these examples, what do they know about the atoms?

## Carbon-12 Carbon-14

For both isotopes, ""^12C, and ""^14C, there are 6 protons, 6 positively charged, massive nuclear particles; this number of protons is what determines the identity of the isotope as carbon. In the ""^12C isotope, there are 6 neutrons, 6 neutrally charged, massive nuclear particles; whereas there are necessarily 8 neutrons in the ""^14C isotope. Capisce?