Periodic Trends
| Front | Which element is the greatest exception in the periodic table? |
| Back | Hydrogen, there is no completely suitable position for it in the periodic table. |
| Front | How does the reactivity of Group 2A elements differ from Group 1A elements? |
| Back | Group 2A elements (alkaline earth metals) are somewhat less reactive than the alkali metals. |
| Front | What do the elements in the Group 6A group, particularly oxygen, like to form compounds with? |
| Back | They tend to accept two electrons to form ions (O²⁻, S²⁻, Se²⁻, Te²⁻) and form many molecular compounds with nonmetals. |