Chapter 1 Multiple Choice Questions

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. The chemistry of the rare earth elements did not develop until the mid-20^th century. Which of the following factors did not contribute to this relatively late start?

The elements occur as mixtures in their ores correct incorrect

Lack of techniques to determine purity of the elements correct incorrect

Difficulty in separation of the elements correct incorrect

Rarity of the elements. correct incorrect

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. Which of the following is the origin of naturally occurring ²³¹Pa and ²²⁷Ac?

Radioactive decay of ²³⁸U correct incorrect

Radioactive decay of ²³⁹Pu correct incorrect

Radioactive decay of ²³⁵U correct incorrect

Radioactive decay of ²⁴¹Am correct incorrect

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. Which lanthanoid elements have the most stable +2 oxidation state?

Ce and Tb correct incorrect

La and Lu correct incorrect

Eu and Yb correct incorrect

Sm and Tm correct incorrect

Gd and Lu correct incorrect

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. Select the incorrect statement from the list below.

Thorium (an actinoid) mainly occurs in an ore that also contains lanthanoids. correct incorrect

The lanthanoid elements are rare. correct incorrect

The naturally occurring lanthanoid elements are less abundant than mercury. correct incorrect

Promethium is the only lanthanoid element that does not occur naturally. correct incorrect

Lanthanoid ores always contain mixtures of lanthanoid elements. correct incorrect

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. Select the incorrect statement from the list below.

4f orbitals have 3 angular nodes and no radial nodes. correct incorrect

5f orbitals have 3 angular nodes and 1 radial node. correct incorrect

5f orbitals of the early actinoids have a greater radial extent than 4f orbitals of lanthanoids. correct incorrect

The 4f orbitals of the lanthanoids are important in bonding. correct incorrect

5f orbitals of early actinoids are destabilized due to relativistic effects. correct incorrect

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. Select the correct statement from the list below.

The most stable oxidation state for U is +3. correct incorrect

The most stable oxidation state for Cm is +3. correct incorrect

U has only two accessible oxidation states. correct incorrect

Th has three accessible oxidation states correct incorrect

The highest oxidation state for Pa is +6. correct incorrect

The most stable oxidation state for No is +3 correct incorrect

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. Select the incorrect statement from the list below.

Metallic radii do not decrease steadily from La to Lu. correct incorrect

The lanthanoid contraction has an impact on coordination chemistry of the lanthanoid elements. correct incorrect

The lanthanoid and actinoid contractions are due only to electrostatic effects. correct incorrect

The lanthanoid and actinoid contractions are due to a combination of electrostatic and relativistic effects. correct incorrect

The similarity in 6-coordinate radii for Nb⁵⁺ (78 pm) and Ta⁵⁺ (78 pm) is explained by the lanthanoid contraction. correct incorrect

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. Select the incorrect electron configuration from the list below.

Lu: [Xe]4f¹⁴5d¹6s² correct incorrect

Eu³⁺: [Xe]4f⁶ correct incorrect

Gd: [Xe]4f⁸6s² correct incorrect

Tm³⁺: [Xe]4f¹² correct incorrect

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. Select the incorrect electron configuration from the list below.

U: [Rn]5f³6d¹7s² correct incorrect

Th: [Rn]6d²7s² correct incorrect

Lr: [Rn]5f¹⁴6d¹7s² correct incorrect

Pa²⁺: [Xe]5f²6d¹ correct incorrect

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. Select the correct statement from the list below:

Eu²⁺ is more stable than Eu³⁺ correct incorrect

Ce³⁺ is more stable than Ce⁴⁺ correct incorrect

Yb²⁺ is more stable than Eu²⁺ correct incorrect

Tb⁴⁺ is more stable than Ce⁴⁺ correct incorrect