Sodium needs to lose one electron to become a noble gas element.

Here's why:

* Sodium (Na) has 11 electrons. Its electron configuration is 2, 8, 1.

* Neon (Ne), the nearest noble gas, has 10 electrons (2, 8).

* By losing its outermost electron, sodium achieves the same electron configuration as neon, which is a stable configuration with a full outer shell.