Here's why:

* Atoms are neutral: Atoms naturally have a balanced number of protons (positively charged) and electrons (negatively charged).

* Sodium's electron configuration: Sodium (Na) has 11 protons and 11 electrons. Its electron configuration is 2-8-1, meaning it has one electron in its outermost shell.

* Tendency to lose electrons: Sodium, like other alkali metals, has a strong tendency to lose its outermost electron to achieve a stable electron configuration like the noble gas Neon (2-8).

* Cation formation: When sodium loses its electron, it becomes a positively charged ion called a sodium cation (Na+). This is because it now has 11 protons and only 10 electrons.