1. How are the second-shell atoms "built up" one after the other from lithium to neon?

2. Why are the second-shell atoms larger than hydrogen and helium?

3. Why do the second-shell atoms decrease in size from lithium to neon?

4. Which of the second-shell elements are metals, and which are nonmetals? Do the metals have a nearly empty second shell, or a nearly full second shell?

5. How many electrons can be accommodated in the second shell? What element has this shell completely filled? Which first-shell element does it resemble in chemical behavior? What chemical behavior is characteristic of these two elements?

6. Which of the pure elements in the second-shell series are solids at room temperature, which are liquids, and which are gases?