How many electrons do metals have at the outer energy level?

Metals are chemical elements that, in reactions, exhibit the properties of reducing agents, that is, they donate electrons to other chemical elements. Because the atom is most stable when its outer energy level is complete. Metals donate electrons, since there are few of them on the external level and they are easier to donate than to attach to complete it. Therefore, they have from 1 to 3 electrons at the external energy level.
Metals are elements of the main subgroups 1-3 groups and elements of all secondary subgroups in the table.