Answer
Sodium gives up an electron.
Work Step by Step
The sodium atom has only one electron in the valence shell. It has eight electrons in the second shell (orbital) and two electrons in the first shell ( nearest the nucleus). So the atom has 11 protons, 12 neutrons and eleven electrons (2.8.1 electrons). It is easy, energetically, for the atom to give up the outermost (valence) electron and become a positively ion (Na+).
