Sodium (Na) has one valence electron in its outer shell. To achieve a stable electron configuration, it needs to lose this one electron, leaving it with a complete octet in the shell below.

Here's how it works:

1. Electron Loss: When sodium reacts with another element, it loses its single valence electron. This results in a sodium ion (Na+) with a +1 charge.

2. Octet Formation: By losing the electron, sodium now has a full outer shell with 8 electrons, fulfilling the octet rule.

For example, when sodium reacts with chlorine (Cl), which has 7 valence electrons, sodium loses its electron to chlorine. This forms sodium chloride (NaCl):

* Sodium (Na): [Ne]3s¹ → Na+ + e- (loses one electron)

* Chlorine (Cl): [Ne]3s²3p⁵ + e- → Cl- (gains one electron)

Both sodium and chlorine now have a stable octet configuration, making the compound stable.

In summary: Sodium obeys the octet rule by losing its single valence electron to achieve a full outer shell of 8 electrons. This results in the formation of a positively charged sodium ion (Na+), which is more stable than the neutral atom.