Why does a sodium atom form a Na⁺ ion instead of Na⁻ ?

A sodium atom has one electron in its outermost shell. It tends to lose that electron to reach a more stable electron arrangement, leaving it with one more proton than electrons and a +1 charge. So it forms Na⁺ by losing one electron, not by gaining one as Na⁻ would.

AI-written and checked against the verified answer.