Barium Barium is the 14th most common element of the Periodic Table of Elements. It makes up 1/2000th of the crust of the earth. Its atomic number is 56, and its atomic symbol is Ba. The atomic weight of Barium is 137.34. Barium is a silver-colored metal. Barium is in group 2 (or IIa) of the periodic table. It belongs to the alkaline earth group. The melting point of Barium is 725 degrees C, and its boiling point is 1640 Degrees C. It has a specific gravity of 3.51 g/cm. Barium is a metallic element. Some of its properties are that it is heavy, highly reactive, soft, and when pure it is silvery white like lead. It is slightly harder than lead, though. In nature, it is always found com