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Lanthanides are rare earths, but one of ...

Lanthanides are rare earths, but one of them is not available naturally. The element under consideration is 

A

Dy

B

Eu

C

Nd

D

Pm

Text Solution

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The correct Answer is:
To solve the question regarding which lanthanide is not available naturally, we can follow these steps: ### Step 1: Understand the Lanthanides The lanthanides are a series of 15 elements in the periodic table, from lanthanum (La) to lutetium (Lu). They are often referred to as rare earth elements. ### Step 2: Identify the Unique Element Among the lanthanides, most of them are found in nature, but there is one element that is not found naturally. This element is known for being radioactive and is often produced synthetically. ### Step 3: Determine the Element The element that is not found naturally among the lanthanides is Promethium (Pm). It is the only lanthanide that does not have a stable isotope and is not found in the Earth's crust. ### Step 4: Conclude the Answer Therefore, the answer to the question is that the element under consideration is Promethium (Pm). ### Final Answer: Promethium (Pm) is the lanthanide that is not available naturally. ---
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