krypton in a natural sample, which is 0.83% 78Kr (molar mass 77.92 g/mol), 1.75% 80Kr (molar mass 79.91 g/mol), 11.13% 82 Kr (molar mass 81.91 g/mol), 12.09% 83 Kr (molar mass 82.92 g/mol), 56.82% 84Kr (molar mass 83.91 g/mol), and 17.38% 86Kr (molar mass 85.91 g/mol).