Answer:
2-
Step-by-step explanation:
For an element to be stable, it must follow the octet rule: an atom will gain, lose or share electrons until its valence shell is complete with 8 electrons.
An element with the valence electron configuration ns²np⁴ has 6 (2+4) electrons in its valence shell. Thus, in order to fulfill the octet, it will gain 2 electrons. As a consequence, it will form an anion with charge 2-.