South Pasadena AP Chemistry

Hillsboro • AP Chemistry Name ______Period ___ Date ___/___/___

9 • Periodic Trends Periodic Trends Worksheet

1. Atomic radius is the distance between the center of an atom’s nucleus and its ______.

2. Why does atomic radius increase down a column?

3. Why does atomic radius decrease across a period?

4. Ionization energy is the a. amount of energy needed to add an electron to an atom. b. amount of energy needed to remove an electron from an atom. c. energy change that occurs when an electron is added to an atom. d. ability of an atom to attract electrons in a chemical bond.

5. How does the periodic trend for atomic radius (an atom’s size) compare to the periodic trend for ionization energy? Why?

6. Arrange the following groups of atoms in order of increasing size (smallest to largest). a. Be, Mg, Ca ______

b. Te, I, Xe ______

c. Ga, Ge, In ______

7. Arrange the atoms in question #33 in order of increasing first ionization energy (lowest to highest).

a. ______

b. ______

c. ______

8. Explain why atoms become smaller as positive ions and why they become larger as negative ions. (Be specific!) 9. Which of the following atoms is the largest: a sodium atom, a sodium ion, or a potassium atom?

10. Define electronegativity.

11. Why are there no recorded electronegativity values for helium, neon, or argon?

12. Which element has the highest electronegativity? ______

13. Down a column, electronegativity a. increases. b. decreases. c. stays the same. d. can’t be measured.

14. Electron affinity is the a. amount of energy needed to add an electron to an atom. b. amount of energy needed to remove an electron from an atom. c. energy change that occurs when an electron is added to an atom. d. ability of an atom to attract electrons in a chemical bond.

15. Compare the electron affinities of metals and nonmetals.