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What is the trend for ionization energy?

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What is the trend for ionization energy?

  1. 1. Launch: 9/24   Grab your binder and immediately take a seat   Place Textbook HW on desk 5. Which of the following atoms has the largest atomic radius? a. oxygen (O) b. phosphorus (P) c. sulfur (S) d. chlorine (Cl)
  2. 2. What is the trend for ionization energy? Mr. Heffner 9/24/09
  3. 3. Review: Atomic Radius Decreases Increases
  4. 4. IV. Ionization Energy A.  What is ionization energy? 1.  The energy it takes to remove an electron from an atom 2.  Atoms can have multiple ionization energies i.  First ionization energy – the energy it takes to remove the first electron ii.  Second ionization energy – the energy it takes to remove the second electron iii.  Third ionization energy – the energy it takes to remove the third electron
  5. 5. IV. Ionization Energy B.  What is the trend for first ionization energy? 1.  Ionization energy increases across a period (LR) i.  As the number of protons increases, atomic radius decreases ii.  It is harder to take an electron off a small atom, so ionization energy increases
  6. 6. Chihuahua Story   I am a dog walker and everyday I walk 8   The stronger I am, the closer I can pull them towards me   The closer they are to me, the harder they are to steal!
  7. 7. IV. Ionization Energy B.  What is the trend for first ionization energy? 2.  Ionization energy decreases down a group (TopBottom) i.  As the number of electrons increases, atomic radius increases ii.  It is easier to take an electrons off a large atom, so ionization energy decreases
  8. 8. Chihuahua Story   I am a dog walker and now I have 9   I can’t fit any more around me, need a longer leash   It is easier to steal one when it is farther away!
  9. 9. IV. Ionization Energy Increases Decreases
  10. 10. IV. Ionization Energy A.  What is the trend for second & third ionization energy? 1.  The trend is the same as first ionization energy 2.  However, the amount of energy is always larger than first i.  After one electron is removed, the protons pull the remaining electrons closer to the nucleus making the atom smaller ii.  It is harder to take an electron off a small atom, so second ionization energy is larger than first
  11. 11. Practice Questions 1.  What is ionization energy? 2.  Describe the trend for ionization energy. How does it compare to atomic radius? 3.  Which has a larger ionization energy, P or S; F or Cl; Li or Cs; Pt or Ni; Fr or F; Se or O? 4.  Which element in group 2 has the largest ionization energy? The smallest? 5.  Magnesium has a first ionization energy of 737.7 kJ/ mol and second ionization energy of 1450.7 kJ/mol. Use what you know to explain this phenomenon in at least two complete sentences.
  12. 12. Homework   Textbook Problems:   Pg. 141 Section Review: #1, 5, 11, 12, 13   Finish Practice Problems   Start reviewing for Monday’s Unit #2 Exam!   lpschem.wordpress.com
  13. 13. Exit Slip 1. Ionization energy is the a. number of stable ions formed by an atom. b. number of protons and neutrons in an atom. c. energy it takes to remove an electron from an atom. d. distance from the nucleus to the valence ring.
  14. 14. Exit Slip 2. In general, how does ionization energy vary throughout the periodic table? a. it decreases across a period from left to right, and decreases down a group from top to bottom b. it increases across a period from left to right, and increases down a group from top to bottom c. it increases across a period from left to right, and decreases down a group from top to bottom d. It decreases across a period from left to right, and increases down a group from top to bottom
  15. 15. Exit Slip 3. Which of the following correctly describes the relationship between first and second ionization energy? a. First ionization energy is always larger than second b. Second ionization energy is always larger than first c. First ionization energy describes positively-charged ions, while second ionization energy describes negatively-charge ions d. First ionization energy describes negatively-charged ions, while second ionization energy describes positively-charge ions
  16. 16. Exit Slip 4. Which of the following atoms has the smallest first ionization energy? a. lithium (Li) b. beryllium (Be) c. sodium (Na) d. magnesium (Mg)
  17. 17. 5. The chart above shows the relationship between the first ionization energy and the increase in atomic number. The letter on the chart that represents the noble gases is: a. W b. X c. Y d. Z

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