How many neutrons are there in Carbon?

From 6 to 8.

The chemical element Carbon has three natural isotopes – i.e., may have three different neutron numbers. The most abundant isotope is carbon-12 (98.89%), with 6 neutrons; carbon-13 has 7 neutrons and is rare (1.11%). Finally, carbon-14, which has 8 neutrons, is radioactive and very rare; this isotope is used in radiocarbon dating (source: “Essential AS Chemistry for OCR”).