3) explain why nacl2 does not form

Because it does not compensate each other. The valence of Na is +1 and the valence of Cl is -1. So if yoy have Cl twice its valence is -2 which does not compensate +1 of Na.

Explanation:

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates