gw2 best enrichment 2024|MetaBattle Wiki Barium Valency. Barium has 2 electrons in the outermost shell of its atom. The outermost shell is slaostermed as a valence shell. Hence, the valency of barium is 2. It can lose these two electrons to attain the +2 oxidation state. Crack BSF Head Constable/ASI with India’s Best Teachers & Coachings. Subscribe