What did you include in your response? Check all that apply. All elements in group 13 have 3 valence electrons. Losing electrons during chemical reactions causes metallic behavior in elements. It is easier to lose 3 electrons than it is to gain 5, so most group 13 elements behave as metals. Having fewer electron shells makes it easier to gain electrons. Boron has so few electron shells that it is just as easy for it to lose electrons as it is to gain electrons, so it behaves like a metalloid.