1. Of the following oxides, __________ is the most acidic.

2. Of the following elements, __________ has the most negative electron affinity.

3. Which element is solid at room temperature?

4. Of the following statements, __________ is not true for oxygen.

5. The substance, __________ is always produced when an active metal reacts with water.

6. Of the halogens, which are gases at room temperature and atmospheric pressure?

7. Sodium is much more apt to exist as a cation than is chlorine. This is because __________.

8. In which of the following atoms is the 2s orbital closest to the nucleus?

9. Of the elements below, __________ is the most metallic.

10. Consider the general valence electron configuration of ns²np5 and the following statements:
(i) Elements with this electron configuration are expected to form -1 anions. (ii) Elements with this electron configuration are expected to have large positive electron affinities. (iii) Elements with this electron configuration are nonmetals. (iv) Elements with this electron configuration form acidic oxides.
Which statements are true?

11. Of the following elements, which has the largest first ionization energy?

12. In general, as you go across a period in the periodic table from left to right:
(1) the atomic radius __________; (2) the electron affinity becomes __________ negative; and (3) the first ionization energy __________.

13. The oxide of which element below can react with hydrochloric acid?

14. Which of the following is not a characteristic of metals?

15. An alkali metal forms a compound with chlorine with the formula __________. (The symbol M represents any one of the alkali metals.)

16. Oxides of the active metals combine with water to form __________.

17. Which one of the following compounds produces a basic solution when dissolved in water?

18. Which nonmetal exists as a diatomic solid?

19. Which equation correctly represents the first ionization of calcium?

20. The most common sulfur ion has a charge of __________.

21. The atomic radius of main-group elements generally increases down a group because __________.

22. In which of the following atoms is the 3s orbital closest to the nucleus?

23. What is the coefficient of H₂O when the following equation is completed and balanced?
Ba (s) + H₂O (l) . ________

24. 2 F₂ (g) + 2 H₂O (l) . __________.

25. The reaction of potassium metal with elemental hydrogen produces __________.