A salt, like calcium chloride, consists of many ions, in this case #Ca^(2+)# and #Cl^-#. If the salt is in its solid state you can't say with calcium and which chloride ions belong together, because they are in a crystal grid, and every positive ion is surrounded by negative ions in a certain proportion and vice versa. And this proportion (in the case of #CaCl_2#) is 1:2.
Note:
For sodium chloride #NaCl# it's a bit easier to visualize:
Every #Na^+# ion has six #Cl^-# neighbours: above, below, left, right, in front and at its back. Same goes for every #Cl^-# ion. If you look through a #NaCl# crystal you will see #Na-Cl-Na-Cl...# in all three perpendicular directions.
