Across 1. A metal used in batteries but not pencils 2. This element is found in the most odorous compounds 3. Its aqueous 2+ ion has a characteristic blue color 4. Bananas are rich in its cation 5. The noble gas with the second-lowest densi 6. Its hydride is the most common basic gas
Oxygen(O) Sulfur() Selenium(Se) Tellurium(Te) Polonium(Po) 也称为成矿元素(ore--forming elements), because many metal ores are oxides and sulfides Electron configuration: ns2npt