To determine how many electrons each group loses or gains, we need to know which specific elements or groups you are referring to. Different elements have different numbers of electrons in their outer shells, and they gain or lose electrons to achieve a stable electron configuration.
For example, in Group 1 of the periodic table (alkali metals), such as sodium (Na), the outermost electron is easily lost, resulting in a +1 charge. In Group 17 (halogens), such as chlorine (Cl), they gain one electron to achieve a full outer shell, resulting in a -1 charge.
If you could provide more information about the specific groups or elements you are referring to, I can provide a more detailed answer.