Download - What is the trend for ionization energy?
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)
What is the trend for ionization energy?
Mr. Heffner 9/24/09
Review: Atomic Radius In
crea
ses
Decreases
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
IV. Ionization Energy B. What is the trend for first ionization energy?
1. Ionization energy increases across a period (LR) 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
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The stronger I am, the closer I can pull them towards me
The closer they are to me, the harder they are to steal!
IV. Ionization Energy B. What is the trend for first ionization energy?
2. Ionization energy decreases down a group (TopBottom)
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
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I can’t fit any more around me, need a longer leash
It is easier to steal one when it is farther away!
IV. Ionization Energy D
ecre
ases
Increases
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
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.
Homework Textbook Problems:
Pg. 141 Section Review: #1, 5, 11, 12, 13
Finish Practice Problems
Start reviewing for Monday’s Unit #2 Exam!
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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.
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
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
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)
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