Lanthanoids and actinoids electronic configuration oxidation states and contraction - Question Bank

1. The chemical similarity between Zr (4d) and Hf (5d) is attributed to:
A) Lanthanoid contraction
B) Actinoid contraction
C) Diagonal relationship
D) Periodic trends
2. Which element is the first member of the actinoid series to show a stable +7 oxidation state?
A) Thorium (Th)
B) Protactinium (Pa)
C) Uranium (U)
D) Neptunium (Np)
3. The trend in ionic radii across the actinoid series is similar to that of the lanthanoids, but generally more pronounced due to:
A) Better shielding of 5f electrons
B) Poorer shielding of 5f electrons
C) Involvement of 7s electrons
D) Higher nuclear charge
4. The compound PuO2 is an example of Plutonium in which oxidation state?
A) +2
B) +3
C) +4
D) +6
5. The electronic configuration of Lutetium (Lu) is [Xe] 4f^14 5d^1 6s^2. Its common oxidation state is:
A) +1
B) +2
C) +3
D) +4
6. The electronic configuration of Gadolinium (Gd) is [Xe] 4f^7 5d^1 6s^2. Its common oxidation state is:
A) +2
B) +3
C) +4
D) +5
7. Which of the following statements about actinoids is incorrect?
A) They exhibit a wide range of oxidation states.
B) All actinoids are radioactive.
C) They are generally more reactive than lanthanoids.
D) Their compounds are usually diamagnetic.
8. Which of the following statements about lanthanoids is incorrect?
A) They exhibit mainly +3 oxidation state.
B) Their compounds are generally colorless.
C) Lanthanoid contraction affects the properties of elements in the 3rd transition series.
D) They are generally less reactive than actinoids.
9. The compound UO2 is an example of Uranium in which oxidation state?
A) +2
B) +3
C) +4
D) +6
10. The basicity of the oxides of lanthanoids decreases as the atomic number increases. Which oxide is the most basic?
A) CeO2
B) Nd2O3
C) Eu2O3
D) La2O3
11. Which of the following lanthanoid ions is paramagnetic?
A) La^3+
B) Yb^2+
C) Ce^4+
D) Eu^3+
12. Which of the following lanthanoid ions is diamagnetic?
A) Ce^3+
B) Pr^3+
C) Nd^3+
D) Lu^3+
13. Lanthanum (La) and Yttrium (Y) are often grouped together despite La being a lanthanoid and Y not. This is due to:
A) Similar ionic radii
B) Similar electronic configurations
C) Similar atomic radii
D) Similar chemical properties
14. The metallic radii of Zr (4d) and Hf (5d) are very similar because:
A) Of lanthanoid contraction
B) Of actinoid contraction
C) They belong to the same period
D) They have the same number of valence electrons
15. Which of the following actinoids is commonly found in +7 oxidation state?
A) Thorium (Th)
B) Uranium (U)
C) Neptunium (Np)
D) Plutonium (Pu)
16. Actinoids form aqueous ions with oxidation state +3, +4, +5, +6, and +7. The stability order of these oxidation states is generally:
A) +3 > +4 > +5 > +6 > +7
B) +7 > +6 > +5 > +4 > +3
C) +3 > +5 > +4 > +6 > +7
D) +4 > +3 > +5 > +6 > +7
17. The element with electronic configuration [Rn] 5f^14 6d^1 7s^2 is:
A) Thorium (Th)
B) Protactinium (Pa)
C) Lawrencium (Lr)
D) Nobelium (No)
18. The element with electronic configuration [Rn] 5f^3 6d^1 7s^2 is:
A) Uranium (U)
B) Neptunium (Np)
C) Plutonium (Pu)
D) Americium (Am)
19. The oxidation state +2 is relatively stable for which lanthanoid?
A) Ce
B) Pr
C) Nd
D) Sm
20. The oxidation state +4 is relatively stable for which lanthanoid?
A) Sm
B) Eu
C) Tb
D) Yb
21. Which lanthanoid has the electronic configuration 4f^14 6s^2?
A) Ytterbium (Yb)
B) Lutetium (Lu)
C) Thulium (Tm)
D) Erbium (Er)
22. Which lanthanoid has the electronic configuration 4f^7 5d^1 6s^2?
A) Europium (Eu)
B) Gadolinium (Gd)
C) Terbium (Tb)
D) Dysprosium (Dy)
23. The basicity of oxides and hydroxides decreases in the order:
A) La(OH)3 > Ce(OH)3 > Pr(OH)3 > Nd(OH)3
B) Nd(OH)3 > Pr(OH)3 > Ce(OH)3 > La(OH)3
C) La(OH)3 > Nd(OH)3 > Ce(OH)3 > Pr(OH)3
D) Ce(OH)3 > La(OH)3 > Nd(OH)3 > Pr(OH)3
24. Which of the following pairs of elements would have similar properties due to actinoid contraction?
A) Zr and Hf
B) La and Ac
C) Th and Pa
D) U and Np
25. Actinoid contraction is more pronounced than lanthanoid contraction due to:
A) Better shielding by 5f electrons compared to 4f electrons
B) Poorer shielding by 5f electrons compared to 4f electrons
C) Involvement of 6d electrons in bonding
D) Higher electronegativity
26. Which of the following is NOT a characteristic of actinoids?
A) Exhibit variable oxidation states
B) Form colored compounds
C) Generally less reactive than lanthanoids
D) All are radioactive
27. Actinoids are generally more reactive than lanthanoids because:
A) Their 5f electrons are less effectively shielded
B) Their 4f electrons are less effectively shielded
C) They have higher ionization energies
D) They have smaller atomic radii
28. Which actinoid is known for its +6 oxidation state in compounds like UO3?
A) Thorium (Th)
B) Protactinium (Pa)
C) Uranium (U)
D) Neptunium (Np)
29. Which is the most common oxidation state for actinoids?
A) +2
B) +3
C) +4
D) +5
30. Actinoids exhibit a greater number of oxidation states compared to lanthanoids due to:
A) Closely spaced energy levels of 5f, 6d, and 7s orbitals
B) Distant energy levels of 5f, 6d, and 7s orbitals
C) Stable f^0 and f^14 configurations
D) Inertness of 7s electrons
31. The filling of electrons in which subshell is characteristic of actinoids?
A) 3d
B) 4f
C) 5f
D) 6d
32. Which element marks the end of the actinoid series?
A) Actinium (Ac)
B) Thorium (Th)
C) Lawrencium (Lr)
D) Uranium (U)
33. Which element marks the beginning of the actinoid series?
A) Actinium (Ac)
B) Thorium (Th)
C) Lawrencium (Lr)
D) Uranium (U)
34. The general electronic configuration of actinoids is:
A) 4f^(1-14) 5d^(0-1) 6s^2
B) 5f^(1-14) 6d^(0-1) 7s^2
C) 3d^(1-10) 4s^2
D) 4d^(1-10) 5s^2
35. Lanthanoid contraction leads to a significant difference in basicity between:
A) La(OH)3 and Lu(OH)3
B) La^3+ and Lu^3+
C) La and Lu
D) Ce^3+ and Ce^4+
36. Which of the following ions has the smallest radius among the lanthanoids?
A) La^3+
B) Ce^3+
C) Nd^3+
D) Lu^3+
37. The decrease in atomic radius across the lanthanoid series is approximately:
A) 0.1 Å per element
B) 0.01 Å per element
C) 1.0 Å per element
D) 0.5 Å per element
38. Which pair of elements have very similar properties due to lanthanoid contraction?
A) Sc and Y
B) Y and La
C) Zr and Hf
D) La and Ac
39. What is the primary consequence of lanthanoid contraction?
A) Increase in ionic radii down the group
B) Decrease in ionic radii down the group
C) Similar chemical properties of elements in subsequent transition series
D) Increase in ionization energy
40. The phenomenon of lanthanoid contraction is due to:
A) Poor shielding of nuclear charge by d-electrons
B) Poor shielding of nuclear charge by f-electrons
C) High ionization energy
D) Large atomic radii
41. Which lanthanoid exhibits a stable +2 oxidation state due to its f^14 configuration?
A) Europium (Eu)
B) Ytterbium (Yb)
C) Samarium (Sm)
D) Thulium (Tm)
42. Which lanthanoid exhibits a stable +4 oxidation state due to its f^0 configuration?
A) Cerium (Ce)
B) Praseodymium (Pr)
C) Neodymium (Nd)
D) Samarium (Sm)
43. Which lanthanoid ion is known to have a stable +2 oxidation state?
A) Ce^4+
B) Pr^4+
C) Eu^2+
D) Tb^4+
44. Which lanthanoid ion is known to have a stable +4 oxidation state?
A) Eu^2+
B) Yb^2+
C) Ce^4+
D) La^3+
45. Which of the following is a common oxidation state for most lanthanoids?
A) +2
B) +3
C) +4
D) +5
46. The filling of electrons in which subshell is characteristic of lanthanoids?
A) 3d
B) 4f
C) 5f
D) 6d
47. Which element marks the end of the lanthanoid series?
A) Lanthanum (La)
B) Cerium (Ce)
C) Ytterbium (Yb)
D) Lutetium (Lu)
48. Which element marks the beginning of the lanthanoid series?
A) Lanthanum (La)
B) Cerium (Ce)
C) Ytterbium (Yb)
D) Lutetium (Lu)
49. What is the general electronic configuration of lanthanoids?
A) 4f^(1-14) 5d^(0-1) 6s^2
B) 5f^(1-14) 6d^(0-1) 7s^2
C) 3d^(1-10) 4s^2
D) 4d^(1-10) 5s^2
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