Question

Is the electron arrangement in a sodium ion
similar to neon or to argon?​

Answer 1

The answer is “Neon”
Hope this help

Answer 2

Just as some elements attain a noble gas configuration by gaining some extra electrons, other elements can more easily gain that configuration by losing some electrons. For a sodium atom, it is simply closer to get to the same configuration as neon than it is to get to the same configuration as argon.