Neon is an unreactive noble gas. Sodium is an alkali metal which is much more reactive.
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Neon is a noble gas. Its shells are full and spherically symmetric. It is therefore “satisfied” and its electrons are not easily ionized, as reflected by its high ionization energy. Sodium is in Group I, and is an alkali metal. It has a lonely electron in the outermost shell that spends a lot of time far away from the nucleus. Sodium would love to give up that electron to attain a closed shell configuration. Therefore that outermost electron can be ionized relatively easily.