carbon-14, the longest-lived radioactive isotope of carbon, whose decay allows the accurate dating of archaeological artifacts.carbon-14, the longest-lived radioactive isotope

Are there any negative effects of using carbon-14?

Carbon-14 is a low energy beta emitter and even large amounts of this isotope pose little external dose hazard to persons exposed. The beta radiation barely penetrates the outer protective dead layer of the skin of the body. Some 14 C labelled compounds may migrate through gloves and skin.

What would happen if carbon-14 unstable?

Carbon-14 has 8 neutrons and 6 protons. It is unstable because it is above the band of stability. Its n:p. It has too many neutrons for the number of protons, but it would become more stable if it could lose a neutron or gain a proton.