Which of the following ion has highest ionic radius

Options

A. `Sc^(+3)`
B. `La^(+3)`
C. `Ce^(+3)`
D. `Lu^(+3)`

Answer

To determine which of the given ions has the highest ionic radius, we will compare the ionic radii of the four ions provided: Scandium (Sc³⁺), Lanthanum (La³⁺), Cerium (Ce³⁺), and Lutetium (Lu³⁺).

### Step-by-Step Solution:

1. **Identify the Ionic Radii of Each Ion:**
- **Scandium (Sc³⁺):** The ionic radius is 1.06 Å (Angstroms).
- **Lanthanum (La³⁺):** The ionic radius is also 1.06 Å.
- **Cerium (Ce³⁺):** The ionic radius is 0.114 nm (nanometers), which can be converted to Ångstroms:
- 0.114 nm = 1.14 Å (since 1 nm = 10 Å).
- **Lutetium (Lu³⁺):** The ionic radius is 0.85 Å.

2. **Convert All Ionic Radii to the Same Unit:**
- Sc³⁺: 1.06 Å
- La³⁺: 1.06 Å
- Ce³⁺: 1.14 Å
- Lu³⁺: 0.85 Å

3. **Compare the Ionic Radii:**
- Sc³⁺: 1.06 Å
- La³⁺: 1.06 Å
- Ce³⁺: 1.14 Å
- Lu³⁺: 0.85 Å

4. **Determine the Highest Ionic Radius:**
- Among the values, Ce³⁺ has the highest ionic radius of 1.14 Å.

5. **Conclusion:**
- The ion with the highest ionic radius is **Cerium (Ce³⁺)**.

### Final Answer:
The ion with the highest ionic radius is **Cerium (Ce³⁺)**.