Question

The IUPAC nomenclature of the element with atomic number 105 is unnilpentium. What is its official IUPAC name?

• A. Lawrencium
• B. Nobelium
• C. Seaborgium
• D. Meitnerium
• E. Dubnium

Hint:

Atomic numbers 104 (Rf) and 105 (Db) are often tested together. Memorize the names of elements 101-118, as they frequently appear in inorganic chemistry questions.

Answer 1

Answer: (E)

Step 1: Understanding the Concept:
Elements with atomic numbers \( Z>100 \) have systematic names based on Latin roots for digits, but they also have official names assigned by IUPAC once their discovery is confirmed.
Step 2: Key Formula or Approach:
Refer to the periodic table for transactinide elements:
104: Rutherfordium (Rf)
105: Dubnium (Db)
106: Seaborgium (Sg)
Step 3: Detailed Explanation:
Atomic number 105:
Root names: un (1), nil (0), pent (5) + ium \(\rightarrow\) Unnilpentium.
The official IUPAC name was contested between American and Soviet researchers and was eventually settled as Dubnium, named after the Joint Institute for Nuclear Research in Dubna, Russia.
Step 4: Final Answer:
The official name is Dubnium.