Based on the information in the table, which two elements are most likely in the same group, and why? Facts about Four Elements Element Atomic mass amu Total electrons Valence electrons Year isolated Bismuth Bi 209 83 5 1753 Nitrogen cap n 14 7 5 1772 Oxygen cap o 16 8 6 1772 Sodium Na 23 11 1 1807 Thallium Tl 204 81 3 1861