Neon has 3 stable isotopes, Ne20, Ne21 and Ne22

The atom clearly shows both sides in full equilibrium or balanced out. Hence the "neutral 5-ending" needed in Fluorine is not needed here.

Neon is a noble gas and has no chemical reactivity. The backbone Carbon nuclet with its 20 triangular faces has the 10 inner and 10 outer electrons divided over these spots effectively neutralizing the whole nucleus, meaning there is no more connection potential, hence a noble gas.