Answer:
The answer to your question is Ca
Explanation:
Ne has its octet completed so, this option is wrong. Neon is stable.
C Carbon has 4 valence electrons not 2, it should lose 4 electrons to complete an octet, so this option is wrong.
N Nitrogen has 5 valence electrons not 2 , so it should gain 3 electrons to complete an octet.
Ca Calcium is the right answer it has to electrons in its outermost shell, it have to lose 2 electrons to complete an octet.