Selenium is a chemical element originated from Moon (with the Greek name selene). It was first mentioned in 1817 and observed by J. Berzelius and G. Gahn. The isolation was later accomplished and announced by J. Berzelius and G. Gahn. “Se” is the canonical chemical symbol of selenium. Its atomic number in the periodic table of elements is 34 with location at Period 4 and Group 16, belonging to the p-block. The relative atomic mass of selenium is 78.96(3) Dalton, the number in the brackets indicating the uncertainty.
Bismuth is a chemical element originated from the German ‘Bisemutum’ a corruption of ‘Weisse Masse’ meaning white mass. It was early used in 1753 and discovered by C.F. Geoffroy. “Bi” is the canonical chemical symbol of bismuth. Its atomic number in the periodic table of elements is 83 with location at Period 6 and Group 15, belonging to the p-block. The relative atomic mass of bismuth is 208.98040(1) Dalton, the number in the brackets indicating the uncertainty.
