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

Answer

To determine the atomic number of the element with the IUPAC name "unnilunium," we can break down the name into its components based on the Latin numerical roots used in IUPAC nomenclature for elements with atomic numbers greater than 100.

### Step-by-Step Solution:

1. **Understand the IUPAC Naming Convention**:
- The IUPAC names for elements with atomic numbers greater than 100 are constructed using Latin roots for numbers. Each part of the name corresponds to a digit in the atomic number.

2. **Break Down the Name "unnilunium"**:
- The name "unnilunium" can be split into two parts: "un" and "nil" and the suffix "ium."
- "un" corresponds to the digit 1.
- "nil" corresponds to the digit 0.
- The "un" at the beginning again corresponds to the digit 1.

3. **Construct the Atomic Number**:
- From the breakdown:
- "un" = 1
- "nil" = 0
- "un" = 1
- Therefore, the atomic number can be constructed as follows:
- Combine these digits: 1 (from "un") + 0 (from "nil") + 1 (from "un") = 101.

4. **Conclusion**:
- The atomic number of the element whose IUPAC name is "unnilunium" is **101**.

### Final Answer:
The atomic number of unnilunium is **101**.