12. What is the difference between ionization energy and electron affinity? Could you think of the first ionization energy of the lithium atom as the electron affinity of the Li ion? Is energy absorbed, or given off, when neutal Li adds an electron? When Li adds an electron?

13. What is a calorie, and what does it measure? What is a kilocalorie?

14. A reasonable intake of food for an average human being per day is 2000 kilocalories. A 176-pound man weighs approximately 80 kilograms. If we consider the man to be essentially water (not a bad first approximation), and he used his entire food intake as a source of heat, by how much would his temperature be raised?

15. Why is the first ionization energy higher for first-shell elements (H and He) than for the second-shell elements?

16. Why does the first ionization energy generally increase from lithium to neon?

17. Why would you expect a sudden and dramatic increase between the fourth and fifth ionization energies of carbon? What does this tell you about the reality of the shell model of the atom?