What is the half-life of neon

Neon is an inert gas, with three stable isotopes, Ne20, Ne21, and Ne22.
In my (rather old) reference, there are unstable isotopes known from Ne17 through Ne19, and from Ne23 through Ne25.

Neon is a well known gas through its use in advertising signs. In physics, it enjoys the position of being the first discovery of isotopes of stable elements.
It is the second-lightest of the inert gases, and may be the least reactive element.
Neon is a useful and cheap cryogenic refrigerant.