Why is Lithium a +1 ion and Chlorine a -1 ion?

The answer lies in how many electron there are in the outer shells of each of the elements and how many electrons they can get or give away to gain a fuller outer shell. Lithium has 1 electron in its outer shell and the inner shell has 2 electrons, therefore to gain a full outter shell it needs 7 more electrons but it easier for it to lose an elctron and become a 1+ ion and have a full outer shell of 2. where as Chlorine has 7 electrons on its outer shell and its easier for it to gain an elctron to become 1- rather than lose 7 to become 7+.