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
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.