Question

exam lesson name: chemistry
exam number: 700700rr
exam guidelines
exam instructions
question 5 of 20 :
select the best answer for the question.

1. the rare earth elements include

a. the alkali metals and the transition metals.
b. the lanthanide series and the actinide series.
c. the actinide series and the alkaline earth metals.
d. the lanthanide series and the alkali metals.
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Explanation:

To solve this, we recall the definition of rare earth elements. Rare earth elements are composed of the lanthanide series (atomic numbers 57 - 71) and the actinide series (atomic numbers 89 - 103). Let's analyze each option:

• Option A: Alkali metals (Group 1) and transition metals (d - block) are not rare earth elements. Eliminate A.
• Option B: Lanthanide and actinide series are the rare earth elements. This matches the definition.
• Option C: Alkaline earth metals (Group 2) are not rare earth elements. Eliminate C.
• Option D: Alkali metals (Group 1) are not rare earth elements. Eliminate D.

Answer:

B. the lanthanide series and the actinide series.