1. Periodic Table, Atoms, and Isotopes Review

2. Directions  Use these questions to help you to review and guide your study.

3. Study Questions  1. Which has the fewest valence electrons?  Helium  Xenon  Oxygen  Nitrogen  2. Which element is NOT in the same group as phosphorus?  Antimony  Arsenic  Nitrogen  Oxygen  3. Which is a liquid at room temperature?  Sodium  Uranium  Argon  Mercury

4. Study Questions  4. Fluorine, Bromine, Chlorine, Iodine, and Astatine have the same valence. To which group do these elements belong?  Alkali metals  Alkaline earth metals  Halogens  Noble gases  5. The order of elements in the periodic table is based on  The number of protons in the nucleus  The electric charge of the nucleus  The number of neutrons in the nucleus  Atomic mass  6. Which of the following elements is an alkali metal?  Calcium  Magnesium  Mercury  Sodium

5. Study Questions  7. As you move from left to right across the periodic table, elements  Become less metallic  Have a lower atomic number  Have a lower atomic weight  Become more metallic  8. Most elements are  Metals  Nonmetals  Metalloids  Shiny  9. The order of elements in the modern periodic table is based on an element’s  Atomic number  Name  Chemical symbol  Atomic mass

6. Study Questions  10. Different isotopes of the same element have different  Atomic numbers  Numbers of neutrons  Numbers of protons  Numbers of electrons  11. Which pair of elements would most likely have a similar arrangement of outer electrons and have similar chemical behaviors?  Boron and aluminum  Helium and fluorine  Carbon and nitrogen  Chlorine and oxygen

7. Study Questions  12. What is the maximum number of electrons that can fit into the second shell?  2  8  18  13. What atom has the electron configuration 2,8,5?  Phosphorus  Silicon  Aluminium  14. Which atom is the most stable: F, Ne, Na?  F  Ne  Na

8. Study Questions  15. Which of these elements has two electrons in its outer shell?  Ba  Pb  At  16. Which of these elements has three electron shells?  Boron  Silicon  Potassium  17. What is the electron configuration of calcium?  2,8,8  2,8,8,1  2,8,8,2

9. Answers  1. helium  2. oxygen  3. mercury  4. halogens  5. The number of protons in the nucleus  6. sodium  7. Becomes less metallic  8. metals  9. atomic number  10. Numbers of neutrons  11. boron and aluminum  12. 8  13. phosphorus  14. neon  15. Ba  16. silicon  17. 2,8,8,2