How many neutrons are there in Neon?

From 10 to 12.

The chemical element Neon has three natural isotopes, and all of them are stable (not radioactive): neon-20, with 10 neutrons, neon-21, with 11 neutrons and neon-22, with 12 neutrons. Neon-20 is the most abundant of them (90.5%), followed by neon-22 (9.2%) and neon-21 (0.3%) (source: “Nature’s Building Blocks: an A-Z Guide to the Elements”).