If a sodium atom loses its only valence electron, it becomes a sodium cation, specifically Na⁺. Here's why:

* Sodium (Na) has one valence electron in its outermost shell.

* Losing an electron means the atom now has more protons (positive charge) than electrons (negative charge).

* Cations are positively charged ions, formed when an atom loses electrons.

So, the neutral sodium atom (Na) becomes a positively charged sodium ion (Na⁺).