How many electrons does sodium need to become stable?

Sodium has one electron in its outer shell, so it is only one electron away from the stable configuration of neon. Instead of gaining 7 electrons, sodium usually loses its single outer electron, forming the sodium ion Na+. This makes sodium highly reactive, especially with water, and is why it is found in compounds rather than as a free element in nature. The tendency to lose one electron also explains why sodium belongs to Group 1, the alkali metals. Its chemistry is central to table salt, sodium hydroxide, and many industrial processes.