Here's why:
* Sodium's Electron Configuration: Sodium has 11 electrons. Its electron configuration is 2, 8, 1. This means it has one electron in its outermost shell (the third shell).
* Full Outer Shell: A full outer shell for sodium would have 8 electrons.
* Octet Rule: Atoms tend to gain, lose, or share electrons to achieve a full outer shell (8 electrons, with the exception of Helium which has 2).
Sodium achieves a full outer shell by losing its one valence electron, becoming a positively charged ion (Na+). This is why sodium is highly reactive and readily forms ionic bonds with elements that have a tendency to gain electrons.
