Molybdenum, Mo /məˈlɪbdənəm/ – (Latin Molybdaenum, from Greek molybdos – lead) – a chemical element of group VI of the Mendeleev periodic system, atomic number 42, atomic mass 95.94. Natural molybdenum has seven stable isotopes; 92Mo (15.86%), 94Mo (9.12%), 95Mo (15.70%), 96Mo (16.50%), 97Mo (9.45%), 98Mo (23.75%), 100Mo ( 9.62%).