Synthetic Method for Obtaining Lanthanides

The synthetic method for obtaining lanthanides refers to the process of artificially producing these elements in a laboratory setting. Lanthanides are a group of 15 metallic elements with atomic numbers ranging from 57 to 71. They are often referred to as rare earth metals due to their scarcity in the Earth's crust.

In the case of the given question, the lanthanide obtained by synthetic method is Pm (Promethium).

Explanation:

- Lanthanides: The lanthanides are a series of elements that are commonly found in the f-block of the periodic table. They are known for their similar chemical properties, which make them difficult to separate from each other. The lanthanides are typically obtained from minerals such as monazite and bastnasite.

- Synthetic Method: Synthetic methods involve the creation of lanthanides through artificial means, such as nuclear reactions or particle accelerators. These methods are used when the natural abundance of a particular lanthanide is extremely low or when larger quantities are required for scientific research or industrial applications.

- Promethium (Pm): Promethium is the lanthanide obtained by synthetic methods. It is the only lanthanide that is not naturally occurring on Earth. Promethium has an atomic number of 61 and is highly radioactive. It is primarily produced by bombarding neodymium-146 with neutrons in a nuclear reactor.

- Application: Promethium has limited practical applications due to its high radioactivity and short half-life. However, it has been used in certain niche applications, such as in nuclear batteries, thickness gauges, and as a source of beta radiation for medical purposes.

In conclusion, among the lanthanides, promethium (Pm) is obtained by synthetic methods. Due to its rarity and radioactive nature, promethium has limited practical applications.