1. What is at the center of every atom?
2. What is the atomic symbol for the element cobalt?
3. What role does atomic number play in the periodic table?
4. Distinguish between atomic number and mass number?
5. If two protons and two neutrons are removed from the nucleus of an oxygen-16 atom, a nucleus of which element remains?
6. If an atom has 43 electrons, 56 neutrons, and 43 protons, what is its approximate atomic mass? What is the name of this element?
7. The nucleus of an electrically neutral iron atom contains 26 protons. How many electrons does this iron atom have?
8. Which electrons are most responsible for the properties of an atom?
9. Which has the greatest penetrating power- alpha particles, beta particles, or gamma rays.
10. Why doesn't the repulsive electric force of protons in the atomic nucleus cause the protons to fly apart?
11. What is meant by the half-life of a radioactive sample?
12. What is the half-life of radium-226?
13. What change in atomic number occurs when a nucleus emits an alpha particle? A beta particle?
14. Which is radioactive, carbon-12 or carbon-14?
15. Why is lead found in all deposits of uranium ores?
16. What does the proportion of lead and uranium in rock tell us about the age of rock?
17. How are the particles in a solid arranged differently from those in a liquid?
18. How does the arrangement of particles in a gas differ from the arrangement in liquids and solids?
19. What is a physical property?
20. What doesn't change in a physical change?
21. What is a chemical property?
22. What is a chemical bond?
23. What changes during a chemical reaction?
24. Why is the freezing of water considered a physical change?
25. Why is the rusting of iron considered a chemical change?
26. Which elements tend to form ionic bonds?
27. Which elements tend to form covalent bonds?
28. If it takes 436 kJ to break a bond, how many kilojoules are released when the same bond is formed?
29. What is released in an exothermic reaction?
30. What is absorbed by an endothermic reaction?