Based upon the location of group iv on the periodic table, the ionic charge of the elements in it should be:

Periodic table is a table of elements arranged in periods and groups in terms similar chemical and physical characteristics.The ion charge of an element depends on the number of electrons may loose or gain to form a stable ion. Elements in group iv have four electrons in the outermost energy level, therefore their ionic charge would be +4 or - 4 since they can gain or loose 4 electrons to form ions.

Outermost (valence) electrons