Incorrect statement for radius of 3d series metal/ions:

Options

A. Metallic radius of Mn is higher than that of Cr and Fe
B. `I_(E_(II)` of Mn is greater than Cr
C. Fe, Co, Ni have almost same atomic radius
D. Irregular trend of atomic radius on moving from Sc to Zn

Answer

To determine the incorrect statement regarding the radius of 3d series metal ions, we will analyze the properties and trends of the elements in the 3d series. The 3d series includes the following elements: Scandium (Sc), Titanium (Ti), Vanadium (V), Chromium (Cr), Manganese (Mn), Iron (Fe), Cobalt (Co), Nickel (Ni), Copper (Cu), and Zinc (Zn).

### Step-by-Step Solution:

1. **List the Elements in the 3d Series**:
- The elements are: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn.

2. **Understand the Trends in Atomic Radius**:
- The atomic radius generally decreases across a period due to increasing effective nuclear charge.
- However, in the 3d series, the trend is irregular. Initially, the atomic radius decreases from Sc to Cr, and then it remains relatively constant or slightly increases from Mn to Zn.

3. **Analyze the First Statement**:
- **Statement**: "Metallic radius of Mn is higher than that of chromium and Fe."
- **Analysis**: This statement is generally correct as the atomic radius of Mn is slightly larger than that of Cr and Fe due to the half-filled 3d subshell providing stability and slight increase in size.

4. **Analyze the Second Statement**:
- **Statement**: "Ionization energy of Mn is greater than that of chromium."
- **Analysis**: This statement is incorrect. The ionization energy of Mn is actually lower than that of Cr because Cr has a half-filled 3d subshell (3d5), which is more stable and requires more energy to remove an electron compared to Mn (3d5 4s2).

5. **Analyze the Third Statement**:
- **Statement**: "Fe, Co, and Ni have almost the same atomic size."
- **Analysis**: This statement is correct. The atomic sizes of Fe, Co, and Ni are quite similar due to the balance of effective nuclear charge and screening effect.

6. **Analyze the Fourth Statement**:
- **Statement**: "Irregular trend of atomic radius moving from Sc to Zn."
- **Analysis**: This statement is also correct. The irregularity in the trend is due to the combined effects of effective nuclear charge, screening effect, and inter-electronic repulsion.

7. **Conclusion**:
- The incorrect statement is the second one: "Ionization energy of Mn is greater than that of chromium."

### Final Answer:
The incorrect statement for the radius of 3d series metal ions is: **"Ionization energy of Mn is greater than that of chromium."**