This compound contains the metal sodium (Na) and the non-metal chlorine (Cl). In ionic compounds, the charges of Na and Cl can be determined by referring to the periodic table, giving: Sodium loses one electron to become Na+1 Chlorine gains one electron to become Ca-1 Atoms are incredibly small. In order for a compound to exist as a stable solid, the total charge must be zero. (Otherwise, the incredible number of charges would give rise to a huge electrostatic repulsive force, which would tear the material apart). In sodium chloride, the +1 charge on the sodium ion is exactly balanced by the -1 charge on the chloride. The simplest picture of NaCl is a single pair of Na+1 and Cl-1 ions as shown below. However, this diagram suggests that each Na ion is only attached to or surrounded by a single chloride (and vice versa), which is not correct.