When sodium loses an electron, it becomes a positively charged ion, specifically Na⁺.

Here's why:

* Sodium (Na) is a metal and has one electron in its outermost shell.

* Losing an electron makes it more stable, as it now has a full outer shell (like the noble gas neon).

* The loss of a negatively charged electron results in a net positive charge, making it a cation.

So, the chemical symbol for a sodium ion is Na⁺.