Answers (2)
The behavior of an atom is mostly dictated by electric charge. When sodium loses one electron it takes on the stability of a noble gas, neon. The one electron is the only one in its orbital, so it does not take much potential to remove it. To add one electron would be quite difficult because it requires a lot of potential to force it in and there is no stability in the arrangement.
since sodium is a group one element in the periodic table, it has one electron in its outermost shell and in the formation of ions, elements do lose or gain electrons. In this case elements in groups 1, 2, and 3 do lose electrons since they need more elecrons than they have to obtain an octet and those in groups 5, 6 and 7 gain as they have more outermost electrons than they need to obain an octet. Those that lose electrons become positively charged and those that gain electrons become negatively charged. Thus sodium forms a uni positive ion (+)