Sodium (Na) has an atomic number of 11, which means it has 11 electrons. The electronic configuration of sodium is 1s² 2s² 2p⁶ 3s¹. Valence electrons are the electrons in the outermost shell of an atom, which are responsible for chemical bonding. In the case of sodium, there is one electron in the 3s orbital, which is considered its valence electron.

Therefore, a sodium neutral atom has one valence electron.