strontium, barium, and radium have similar electrom configurations
one_of_chemical_elements is strontium. strontium_hydroxide is strong_electrolyte. strontium_hydroxide is ionic_compound. strontium_ion is strontium_atom. strontium_ion is monoatomic_cation. strontium_oxide is chemical_compound. strontium_90 is strontium. strontium is metallic_element. protium is unium.