What is the atomic number of an element whose IUPAC name is unnilunium.

Answer

To determine the atomic number of the element whose IUPAC name is unnilunium, we can break down the name according to the IUPAC nomenclature system for elements with atomic numbers greater than 100.

### Step-by-Step Solution:

1. **Understanding the IUPAC Naming Convention**:
- The IUPAC naming convention for elements with atomic numbers greater than 100 uses a combination of prefixes that represent the digits of the atomic number.
- Each digit from 0 to 9 has a corresponding prefix:
- 0 = nil
- 1 = un
- 2 = bi
- 3 = tri
- 4 = quad
- 5 = pent
- 6 = hex
- 7 = hep
- 8 = oct
- 9 = nan

2. **Analyzing the Name "unnilunium"**:
- The name "unnilunium" can be broken down as follows:
- "un" corresponds to 1
- "nil" corresponds to 0
- "un" again corresponds to 1
- "ium" is a common suffix for metallic elements.

3. **Constructing the Atomic Number**:
- Now, we can combine the values represented by the prefixes:
- The first "un" (1) represents the hundred's place.
- "nil" (0) represents the ten's place.
- The second "un" (1) represents the unit's place.
- Therefore, the atomic number can be constructed as:
- 1 (from the first "un") + 0 (from "nil") + 1 (from the second "un") = 101.

4. **Conclusion**:
- The atomic number of unnilunium is 101.

### Final Answer:
The atomic number of the element whose IUPAC name is unnilunium is **101**.

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