AP Chemistry
Unit 2 Review Guide
Name __________________________
Class _______ Date _______
Key Terms:
Quantum mechanics Louis deBroglie Werner Heisenberg Erwin Schrodinger principal energy level shell sublevel subshell orbital
electron spin Aufbau principle Pauli exclusion principle Hund’s rule valence e- core e- electron dot diagram PES Coulomb’s Law
atomic radius
Zeff shielding effect ionic radius
cation
anion
ionization energy electron affinity
electronegativity
Equations:
𝒉
𝝀 = 𝒎∙𝒗
ν
𝑬𝒏 =
−𝟐.𝟏𝟖𝒙𝟏𝟎−𝟏𝟖 𝑱
h∙c
Ephoton = λ
𝒏𝟐
𝑬=𝒌
1.
What is a photon? How is the energy of a photon related to
it’s wavelength and frequency?
2.
Calculate the wavelength of a baseball (0.45 kg) travelling at
half the speed of light (1.5 x 108 m/s).
𝒒𝟏∙ 𝒒𝟐
𝒅
Zeff ∝ (# p – # core e-)
Ephoton = h ∙
13. For each of the following properties, indicate whether fluorine
or iodine has a larger value:
a) electronegativity
c) electron affinity
b) atomic radius
d) ionization energy.
14. Explain why radius of an atom cannot be measured directly.
3.
What did Schrodinger’s equation predict?
15. Which elements are characterized as having their d orbitals
fill with electrons as you move left to right across a period?
4.
Explain Heisenberg’s Uncertainty Principle.
16. What is the difference between a core (a.k.a. shielding)
electron and a valence electron?
5.
How many electrons could exist on the fourth energy level of
an atom?
6.
What information does the orbital filling diagram tell you that
an electron configuration does not?
7.
When filling a p orbital, why do you separate the electrons
into different orbitals, before pairing them up. What is the
name of this rule?
8.
What information does a Lewis dot diagram tell you?
9.
What do the elements in the same period have in common?
17. Explain why it’s harder to remove a shielding electron than a
valence electron from an atom?
18. An element forms an cation when ionized. On what side of
the periodic table is the element located? Explain.
19. What is the Aufbau Principle?
20. What is the Pauli Exclusion Principle?
21. Explain why each successive ionization of an electron
requires a greater amount of energy.
10. What do elements in the same group have in common?
11. How does Bohr's "electron orbits" differ from the "electron
orbitals" as proposed by QM?
22. Na+ and Mg2+ ions each have ten electrons surrounding their
nuclei. Which ion would you expect to have the larger
radius? Explain.
12. Why do some properties of elements repeat in periodic
patterns?
23. Why does 4s subshell fill with electrons before the 3d
subshell?
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24. Draw the Lewis dot diagram, and electron configuration for
the following elements.
Lewis-dot Electron configuration
Sybmol
diagram
(use noble gas shortcut)
35. Order the following groups from highest to lowest ionization
energy.
a. Na, Mg, Al, S
b. Br, F, At, I
c. Cu, Zn, Ga, Se
Ne
36. Describe effective nuclear charge (Zeff).
Cu
S2-
37. Calculate the Zeff for Ca and Br. Can Zeff be used to explain
atomic radius trends? Explain.
U
38. What is ionization energy?
Ca2+
39. Why is the 3rd ionization energy of Mg so much larger than
it’s 2nd IE?
25. How does the atomic radius change from left to right across a
period. Explain why?
40. Why is the ionization energy for Al less than Mg?
26. How does the atomic radius change from top to bottom for a
group. Explain why?
41. In which group are the three species isoelectronic (all have
same # of e-)?
(A) S2-, K+, Ca2+ (B) Sc, Ti, V2+
(C) O2-, S2-, CI- (D) Mg2+, Ca2+, Sr2+
27. How does the ionization energy change from left to right
across a period. Explain why?
42. The ionization energies for element X are listed in the table
below. On the basis of the data, element X is most likely
Ionization Energies for element X (kJ mol-1)
First
Second
Third
Fourth
Fifth
580
1,815
2,740
11,600
14,800
(A) Na
(B) Mg
(C)
Al
(D)
Si
28. How does the ionization energy change from top to bottom
for a group. Explain why?
29. Why do large atoms have small ionization energies?
43. Which property generally decreases across the periodic table
from sodium to chlorine?
(A) 1st ionization energy (B) Atomic mass
(C) Ionic radius
(D) Atomic radius
44. On a PES what conclusion can one draw if two peaks have
the same height?
30. Why are metal ions smaller than their metal atoms?
45. Given the following energy level diagram for an element,
sketch and label the PES spectrum.
31. Why are nonmetal ions larger than their nonmetal atom?
32. Why does F have a higher electronegativity than Li? Be
specific?
33. What electron configuration has the greatest stability?
34. Order the following groups from smallest to largest radii.
a. I, Ba, Cs, Xe
b. Kr, Br, Sr, Se
c. Li, K, Fr, Cs
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